I have a REI DRT 1.1. Their basement intro mountain bike. I’d like to upgrade the forks. I only spend $488 on the whole bike so I’m not really interested in spending money on something like Fox. I ride mainly on improved trails and use it for a security side job on asphalt.

What are some things to consider when choosing and what forks are worth the money for a budget ride?

Thanks.

I'd probably just look at a slightly upgraded bike used and sell yours to offset.

Used bikes are a dime a dozen from COVID.

I got a $5900 bike with 4 miles on it for $3k cash.

That’s going to be tough.  Might as well find a cheap one on eBay if you are set on it.   Do your homework on fitment.

Not worth the upgrade, save the money for the next bike

Looking at a Giant Fathom 2 29” vs  Roscoe 7 29”

Any opinion

Not instantly familiar with either, but a quick look at the fathom 2 online; decent entry level rig, Deore drivetrain is adequate, geometry looks modern, price is right. In general Giant bikes are a good value.
 Their full suspension rigs are on sale now too, some killer deals. Not sure if you think it'd be worth it to you, but FS bikes are pretty great these days. If you think you'd ever get into trail riding, it'l might be worth it.

Giant FS bikes

ETA.
The Trek looks basically comparable, Sram instead of Shimano, but the Giant has slightly more reach, a bit slacker headtube and a dash shorter chainstay length, a bit more progressive geometry than the Trek.