Constant stuttering even on lowest settings

Hmmmm this sounds to me like a graphics card issue more than anything. However if you're not having issues with other games of the same weight then it is something to do with the game itself. First, I would try doing a repair check on Apex. Sometimes patching data gets funky and can corrupt for some unknown reason. If that doesn't work then re-install, restart, and try again. If this still doesn't work check to make sure your updates on your pc are up to date. Also, the age of your graphics card can be an issue but the benchmark seems like its doing fine-ish.

Another possibly problem is something is eating up your GPU data other than the game. So for this you will need task manager to see what is going on there. You might also want to check out your temps with Speccy (free to use and virus free). It will show you some more in detail stats that task manager can't tell you. However, IMO its either some patching that went bad, your card either too old or it being eaten alive by some other program, or you need to check your pc updates.