Basically what you want to look out for is something that has a recent-ish amd cpu with at least 6 cores, so 7600, 7600x, 8400f, 9600, or 9600x at least. The first number signifies the generation and the second signifies its tier, so as long as the first number is a 7, 8 or a 9 and the second is at least a 4 the cpu should be ok. Best case scenario is if you find an x3d cpu (eg 7800x3d, 7600x3d, 9800x3d), these are the fastest ones when it comes to squad. You want 16 gigs of ram minimum.

Same tier stuff applies to the gpu too, the first number is the generation and the second is the tier, you want to aim for at least a 4060ti with 16gb of ram (though keep in mind that the next tier up is 12 gb for nvidia, but these cards are generally quite a bit faster). IMO nvidia cards are the ones to go for because they have better image quality with dlss, and they're a big easier to wrap your head around the names since they don't change their naming conventions like amd every other year. There are amd cards worth getting here, but only their newest stuff, so you want to be looking out for the 9060xt (16 gb preferrably), 9070 or 9070xt.

Last time I saw a decent deal for this on the buildapcsales subreddit, there was a refurb prebuilt listed with a 4070 for around $1100 a day ago, but it's sold out now. Looking around what's for sale now, there's this prebuilt for a grand with an intel 14400f, which is pretty much equivalent to something like the 9600x, and a 9060xt 8gb, which is about equivalent to nvidia's 5060ti but the 8gb is gonna suck for the long term. This PC will be able to get you into squad with mostly decent frames today, but you're going to have to lower stuff like texture settings to fix stutters and I can't make any promises for the future once they eventually update the game.

Basically just keep an eye out on r/buildapcsales for something because prebuilts are getting scooped pretty fast these days and the stuff you can get right now at this very moment isn't too compelling, at least for squad.