In the Iliad, the Dardanians and Mysians are two seperate peoples and always referred to as such. Mysia neighbours Troy/Dardania. In the Aeneid, the Dardanians come to Italy where they meet the Italics already there. Hence the myth is not about the Italics origins.
Strabo says the Dardanian tribe called the Galabri gave Calabria its name. This is where we see the Messapic languages. The Messapic languages, like Albanian, are not satem or centum, they have 3 dorsal rows. They are Illyric languages.
Thracian is a satem language, not like messapic or albanian. It has only 2 rows.
Dardanian, as we see in Messapic inscriptions, is not like thracian.
The most proximate people to thracians are balts, not slavs. So Latvians and Lithuanians have more claim to being close to them linguistically than any slav.
Hence, Messapics called themselves Dardanians, Strabo called them Dardanians, their language is not thracian, it is Albanoid, it preserves the 3 rows.