I do think a pregame shop would be kinda weird for a game like this, especially considering theres different classes with unique loadouts. I think what would be better is an upgrade system. You still have the same tools, but you can use those points to maybe buy more morphine and medkits and stuff, or upgrade ammo capacity, morphine effectiveness, gun damage, armor and armor durability/damage reduction, flashlight strength, etc. I do like the class system because it feels like you're choosing to be a part of a special forces team, and I think that would be lost if you were given too much freedom to give yourself whatever you want assuming you had the money for it.
I was also considering doing something liek that, remaking copycats phenomenon for funsies but i have atrocious work ethic and know I'll never finish it. If i do, it'd be a passion project.