I don't know if this will have any impact or matter at all, but I recently built my PC just for this game, it's a midrange expense PC, i7-14700kf, GeForce 5060, with 64gigs of ram. I totally feel your pain bro, I am still getting killed by people right next to, or right in front of me, the crazy thing is, it tanks too and it happens a lot. Imagine you got killed by a tank 40 or 50M away and cant see it, except for the orange figure that shows you its location after your killed. Not even sure why I'm still playing. I guess I'm hoping for some great improvement. I will say that BF3 and 4 were quite a bit better, you could always get a chopper or tank, but not in 6, I loved flying in the older games, In BF6 I have not been in a chopper yet, they are almost never available.
Also I notice a huge difference when playing redsec, Gauntlet seems to play ok, but going into Battle Royale, I can almost never get a kill in there. Family members have pretty much quit the game, they played on PS5. One is very good, but says when playing on crossplay, he has the same issues, getting killed so easy, and it sounds like you were one shot. The frustration ran him off, so a game that was gonna be our new family game, is now down to just me playing. The other 2 don't play anymore.
We left COD thinking this was gonna be the new best place to gather for good action. COD got ridiculous with the themes and skins. I will say it play better than BF6, overall very disappointed.