So does it only unlock on ones i have tempest or on any gun that is in the game (even if not a single headshot challenge is completed)?
I took a breather throughout 6.5-7.5, played lots of other games (not competitive ones) like Black Myth Wukong, Wuchang, Sekiro, Crewe Motorfest, Forza, hell even played Ace Combat 7 for the first time.
I came back, and genuinely started to love it so much (like that feeling I had in season 1-2, where it was all so new, I wasn't bothered about mistakes, and just enjoyed learning and having fun.
This game changes a lot from season to season, that if you miss a season, its all new again. If you're playing constantly, you get mad when people don't choose to do the best thing available, cos you know what to do.
So genuinely, take some time off from the game, and reset, cos if you're missed and not having fun, why even play? Cos chances are, you're not making money off it or anything, and even if you're Eternity, it's meaningless if you're not enjoying being there.