>>11851172
With something like Comatose, I get very shit performance. With the modified Comatose version which removes the like 20000 decorative grass actors, I find that I can frequently get framerates anywhere between 100 to 120 at the best, and never dipping below 40 at the worst, frequently hovering somewhere around 60 or 70.
That's not the same as that kind of environment, but it's still a large and detailed outdoor environment which is known to be demanding. If I use something like Slaughter Optimizer to slow down monster calls well outside of the map, this can help the frames a bit further (though it makes a bigger difference in more monster intense maps, obviously).

My computer isn't anything special either, it'd be considered average about 5 years ago.
For my purposes, GzDoom isn't perfect in performance, but I rarely find a level which seriously tanks my performance.