Set a minimum frame time for FFmpeg gifs

I’m converting videos into gifs with FFmpeg, but I’m running into an issue that many have encountered before: many gif players refuse to play gifs faster than 50FPS (2 hundredth of a second frame duration). The gif format technically allows up to 100FPS but not all players support that.

I have code now to limit the FPS to 50FPS, but the problem is that FFmpeg, when encoding from a weird fps like 29.97fps, will occasionally generate 1/100 s frames since each frame duration is independent.

I want to, ideally with a single ffmpeg command, generate a GIF of the right speed (not slowing down or speeding up) but without ever generating 1/100 s frames. Is this possible?