(A nice thought-experiment is to ask if Quake could have been coded in TP at all - even if memory hadn't been an issue (I think there was no DOS extender for TP, but I could be wrong).)
So Turbo Pascal (with a whole bunch of x86 asm inclusions) was totally capable of producing Quake-level games. I myself, in the late 90s, discovered the hidden capacities when I learned x86 assembly from Peter Abel's book. Once I got rid of the primitive TP BGI library and switched to VGA 13h, it was an unbelievable level up in abilities to manipulate pixels on the screen!
I might be misremembering but I thought it was more of a Doom-style engine with 3d models instead of sprites for the entities, rather than a full 3d engine like Quake.
The first time I played, I thought "It is just like Quake". Then you start to notice that the levels are pretty limited - it is all narrow corridors with rare small chambers and open spaces, no steep elevation changes, no rooms above rooms... Kinda like Doom. But then, father's examination shows sloped surfaces, shelves and bridges - stuff the Doom engine can't do.
Maybe, for level geometry, it is closer to portal rendering engines like Build. Still looks pretty claustrophobic even compared to Doom and Duke Nukem 3D. I feel the Chasm level designers could've got more variety from that technology, but again, maybe that was some fundamental limitation. Or maybe it is just like FPS were designed in the mid 90s.
Monsters, items and weapons are fully 3D, though. With dynamic lighting!
Additionally most hit games back then were full of inline Assembly, regardless of the high level language, or even written 100% in Assembly.
Turbo Pascal 7 had a DOS extender.
There was Turbo Pascal for Windows 3.1, and with Delphi it started to be even more C++ influence with Pascal syntax, and safety first.