This is a late response (I'm most active on the Discord and check the Board less frequently than I rightfully should), but I remember that fic.

It specifically had to do with a Tonks replacement being isekai'd onto the boat at the end of Part 1 and escaping it with Erina, gaining immortality and a stand because... Reasons, and going on the subsequent bizarre adventures. Iirc it only got up to around the end of part 6.

I don't remember a ton of specific details offhand since I initially found it like a year ago, but it was more of a beige, super condensed recounting of canon ft. an extra character than an outright retelling. Very stations-of-the-canon-y, but with less death. Also, the sue's stand wasn't made of cockroaches. I think it looked like a snake or something. Its power was turning inanimate things into other inanimate things, which, while actually pretty fitting for canon!Tonks, was broken since there weren't any clear limits to it.

As for other Jojo suefic, I haven't done much searching but it probably does exist. It being rare wouldn't surprise me, though. Jojo fics seem to generally understand that the fun part of Stand powers tends to be in inventiveness/general coolness rather than sheer power, from what I've seen.

Edit: Also, nice to meet you!