Its a no-end discussion, in some way, without metrics details and auDNA of the very same pops (place and time).
Surely someones smile when they read my posts (if they do, of course). When I speak of cromagnoid and brnnoid I speak of very close features inherited by far more recent pops. Some smart people think this is ridiculous because new admixtures took place during the periods of Upper-paleolithic and Mesolithic, on great spaces between Western Europe and East-Central Asia. My fealing is that at the phenotypical level, some typical features were not always so new but only the redistribution of ancient traits genetically inherited but not particularly adaptative to selection. By example some tendancies (without adaptative advantage) seem to me bequeathed by West-Central Asian ancient HGs pops which imported these features wave after wave, without too big phenotypical change spite their adaptative auDNA could have evolved for parts with changes of echological places or of climate. When I speak of cromagnoid or brnnoid aspects I refer to external shapes spite I know no isolated genuine cromagnon or brnn stayed intouched even before Mesolithic, their first illegitimate matings beeing between both, as in Bohemia and elsewhere, according to places and time (by instance some old scholars thought both old patterns were found among Balkans Mesolithic people, mixed or not). The eastern models traits ar resumed by true dolichocephaly, large upper face but with a more or less high lower face and narrow bigonial (under jaw) spite broad bizygoma (cheekbones), a not too broad nasal hole, and very receding frontal and very strong browridges, a cranial vault with an arched lateral profile, in fact something brnnlike close which remains in upperpaleolithic combe-capelle ; these tendancies play a role, I think, partly gracilised and in composition, in the so called eurafrican type so in indo-afghan types and in some new components in the Near-Eastern pops, at the period or late Levant Farmers.
Hard to make a sketche of these migrations/mixings : admixture at a high level was not the rule everywhere, and back moves occurred more than a time (glaciation, glaces break-up and later before Neolithic) the rule would be rather a more or less level mix of both great models , with sometimes local choices of sets of traits, and in certain places preponderance of one of both ; new mutations occurred of course but I believe that some old tendancies remained which shape still the features of some today people, partly gracilised.

When we look at metric surveys about Northern Europe, we can read the most of the people - until around 4000 BC and even later in some places and cultures had kept ruggy traits with old features : as a whole, huge heads whatever the statures, rather broad faces, massive all the way, spite dolichocephalic, from hyperdolicho to meso. Relying on readings, Erteblle people as a mean were dolichocephalic, their faces were big, with relatively broad and low faces : they were close to the people of Sredny Stog and Dniestr-Dniepr of LN. Around Baltic lands, until 2500 BC or around (in their very EN), the types were close, but hyperdolicho, high faced, and a bit higher and narrower of face, even if still massive : rather mesoprosop than euryprosop : in all these incomplete descriptions I see the old heritage of dominant cromagnoid and brnnoid features, more brnnoid among pre-Balts pre-Estonian peoplee time. These people the arctics expansion of H. Hubert in in book about the Germanics? - had travelled until East-Baltic lands, Onega and Ladoga lakes, were they entered in contact with SW-Siberian HGs (archaic proto-Uralic type not well differentiated post-ANE, with some features closer to east-asian types) ; ; the result of this new admixture was a more mesocephalic types, with a rather flat horizontal profile of face, a low bridged nose with smaller nasal angle ; surely the future West-Finnic basic type. Seemingly Pit Comb Ware C. people if we consider auDNA, the proto-Uralic type would have been little enough of the so called east-asian DNA (rather northern siberian side) ;
This admixture progressed westwards around 2500 BC and after, MN, until Estonia and Eastern Latvia, not reaching Lithuania.
CWC/Battle Axe C. dolicho high skulled very high faced people came after with true Neolithic.
Their making can be discussed later.

& : personally, I think all this are average measures. The brnn heritage seems to me stronger as a whole than the croma one ; but this advantage varied according to place, croma shaped faces and skulls are still seen in Europe.

DNA level : Latvia and Ukraine Mesolithic and Neolithic : it seems some exchanges occurred between Latvia HGs descendants (who were between WHG and SHG), with introgression of more EHG people, at MN at LN, the influence of CHG is strong : here LN Latvian are almost identical to CWC people on PCAs ; this DNA study sample is helas very scarce. But it seems merking the beginning of introgression from East in Baltic regions at MN, and we can say the auDNA and metrics confirm one another, as very often IMO.
in Ukraina, HG were between SHG and EHG, and Neolithic ones drifted a little bit towards Latvian HG, so we can suggest here a partial osmosis between Ukrainian Neol and Baltic HGs descendants (the admixture runs show in Ukraine N just a bit more of CHG than Ukraine HG where it was already present at low rates) ; Kazarnitsky (metrics) thought Neolithic in Ukraine had received new human elements compared to mesolithic I think in a slight osmosis in Ukraine with a bit of Comb CCC genetically related people (and some more mt-U4) at early Neolithic (?) -

Among novelties, brachycephalisation seems occurring since 8000/6000 BC in some places, very often highlands (mesological selection?) in Western Steppes, the Pit Grave people of Kalmykia had a tendancy to brachycephaly compared to Ukraine HGs and to Ukraine Pit Grave people, tendancy shared with Ukraine, Russia and Latvia Neolithic but with a less flat facial profile and a more protuding nose than these last ones (more ando-afghan input ? More on a dinaric way ? Less of the tiny SW-Siberian HGs input?) - I regreat here again the lack of individuals and mean mesures, what we have today are plottings and dendograms, these last ones without too big sense the more often.
So weak brachycephalisation (at the average level) at those times in some places in Central and East Baltic regions, with possible mix of traits inherited from diverse horizons, for the most among robust pops on the bony angle. I wonder if our borrebies or pseudo-borrebies are not the result of these mixes with diverse results according to preponderence of types or to hazardous recombinations. The so typical (for us) eyelids of some Finnic people are labelled east-asian : in fact they are typical of only some of east-asians, and more than the not always present internal eyefold its the thin triangular aperture and the typical almost rectiligne ascending inferior eyelid that make them remarkable ; surely inherited from the proto-Uralic componant. Some of these eyelids are found also among Scandinavian and even farther in Western Europe spite more seldomly.
& : dinaric itself could be an other recombination with addition of a mediter variant. I avow Im short for dinaric concerning details, only that they does not seem to me a stable type.

to answer you (at last) yes 'croma' as well as 'brnn' lasting influences were present among Erteblle (and other northern preneol. cultures) but the 'borreby'complex ought maybe more to LN-Eneolithic intrusions from East/North-East than to a pure local 'alpinisation' which stayed steadily weak there compared to W-Alps.