This is what I assumed
I tried this with my scenario (a plane with a single edge loop horizontally and vertically), the edit mode performance was perfect. I assume that the same operation as a modifiers would be much heavier though, as that’s usually the story with non-destructive operations.
The edit mode operation does get the job done, but as always, keeping it procedural is preferred. I understand the slider becomes too sensitive when going over a soft limit, but I wonder if this is something people could get used to. What I mean by that is like the subdivision surface modifier; no one actually slides it, you manually type it. This is because people, after using blender or other software’s for a while, realize that it is a very heavy operation. So I wonder if the hard limit of 100 segments could be changed to a soft limit of 100, allowing manual typing above that. Then the slider would indeed become way too sensitive, but I think people could catch on pretty fast that that using the slider at that point is not something you want to be doing, and that you should be typing. If that seems acceptable then I changing the limit to something like 500 would probably be sufficient, if that is still performant then perhaps matching the edit modes 1000 is fine as well. That all depends on performance which I cannot test.