That's older info. There has been multiple improvements and breakthroughs since then. The estimates I have seen say that it could do something like 4-10x (and 40x if we use account model where privacy sucks) and then you can add more rollups on top of the first one.

One big thing that changed recently is BitVM (shared by @robin_linus in December) that could theoretically make zk rollups "almost trustless" on the current bitcoin chain without any soft fork. By "almost trustless" I mean that you can create a setup where you only need one honest actor (e.g. 1 out of 999) to prevent money being rug pulled (which is quite a difference compared to e.g. Liquid, where you need 5 of 9...)