I'm trying to play a longer game, 20x tech multiplier. This necessitates slower enemy expansion, but Rampant doesn't seem to obey vanilla expansions timers. I have mine set to min 30/max 60, but bases with rampant pop up much quicker than that. Is there a way to slow or temporarily halt Rampant expansion?

Perhaps in your case it is worth disabling the "siege" mode. Then only the standard expansion will remain

So disabling siege mode makes it like normal rampant? Havnt played it before and its not updated.

No. This only removes the settlement under the walls. And since Rampant Fixed, unlike the original Rampant, does not settle the rest of the map, then only the standard settlement remains.

How can you make something similar to the original Rampant I answered you here:
https://mods.factorio.com/mod/RampantFixed/discussion/67effd198e782962dba6a711

Yes, I thought id not change the subject of this post but thanks for the answer. I think I will disable the siege and underground and just leave the rest and see how I handle it.

Sounds good, I will give this a try