I don't know where to ask this so I'll just write my question here. Since Betterfps Render Distance is compatible with most mods, does that include optimization mods like Rubidium? [Forge port of Sodium].

It throws an error in the log file when Rubidium is installed, mentioning something about 'mixin apply failed."
I posted this issue in the Rubidium github issue tracker.
Asek3/Rubidium#107 (comment)
Maybe with the help of both mod authors, we will be able to figure out a solid answer.

the 1.18 version actually should work with it, 1.16 doesnt. And I don't think I'd like to get engaged with such a character that Rubidium dev displays, so I'll pass on investing time to make it work