> redrumloa did just the same, still no 140 FPS though

And that's with both faster CPU and faster GPU.

> even more tweaking with .cfg file gave me 102 FPS (no gun, no
> shadows, no gibs, no gun/ammo 3d models...). All right, maybe 140 is
> doable, but at a (great) cost.

Incidentally, said presentation of Quake 3 running with alleged 140 FPS has been recorded on video:

https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=7464&forum=11&start=15
https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=7464&forum=11&start=21

The quality is rather substandard, but maybe you can recognize from one of the recordings which of the tweakings that you just did may or may not have been applied there.