On the flip side, if you do have OpenGL, why not utilise it for unparalleled terminal performance? I've used Kitty for years for that reason, it's incredibly responsive and smooth, a pleasure to use.
Genuinely curious. I've never ran into a situation where the standard terminals felt "sluggish"... barring a slow internet connection sshing.
I used Urxvt for about fifteen years, it didn't feel slow at all. Kitty just _feels_ faster.
[1] The latest video for it is here: https://www.youtube.com/watch?v=99dKzubvpKE