I searched and read in the past, from the internet, multiple things about ancients Saxons.
And what I found is that, during the migration of the Saxons to England, they were carrying a typical weapon, the Seax, which was a longer knife.
The word Seax existed in Old English, meaning a knife.
https://en.wikipedia.org/wiki/Seax (the pronounciation is Seaks)
As a paranthesis, the word Sex is from actual English and is of Latin origins. So it has no link with old Saex word.

The Gaelic speakers of England and Walles and Ireland called these people:
And this is confirmed, by the fact that in Romania, Transylvania, the migrants brought from Lower Saxony were called by the Romance speakers from Romania:
Sas, plural, sasi.

Another theory, is that Saxons comes from the name Saka, that was attributed to Scythians.
I do not deny the theory that some Scythians, which according to genetic research were mostly R1B, have settled in today Lower Saxony and brought with them both the Horse raiding custom and the use of a knife,as a custom.
And from the mixing of these Scythians with local West Germanic people, from those days Lower Saxony, resulted the Ancient Saxons.
Later, a part of the Ancient Saxons migrated to England, having with them Saexs,as defense weapons.