Direct Graphic Rendering -- When is it needed?

Despite my googling and searching, I couldn’t really find a straight answer to this question. So, here we go.

I don’t fully understand how flatpak works, so whenever I install a game via flatpak, I reflexively allow access to DRI (direct rendering interface). This paranoia on whether or not something is using hardware acceleration has led to me avoiding, for instance, the flatpak of Steam. I’ve also noticed that some games crash with it on, but when I turn it off performacne seems fine. That said, these are mostly low-resource games, as opposed to my other games that need rendering access.

So here is my question. Is enabling DRI access necessary for GPU usage? For vulkan, mesa, etc? If I install a game through flatpak, say, through Steam, and it’s top of the line, does enabling DRI do anything or not? Is the graphics interface handled entirely by sandboxed drivers? If so, how do they access the GPU without DRI? Should everyone be running Steam with DRI enabled? If so, why isn’t it a default permission on any program? Should I turn it off?

Apologies for this hyper specific question. I’m sure the answer is out there somewhere, but I keep finding answers to questions related to this one, but not this question itself.

Having read more into it this seems to be a UX problem on KDE’s end. I use kcm-flatpak to manage my perms, and they have graphics access as separate from device access. But according to the spec, device access grants graphics access, and almost all flatpaks in question already had device access.
See: Sandbox Permissions - Flatpak documentation