When one sub is the problem
Sometimes the issue isn't your whole history - it's one community. A subreddit tied to a phase you've moved past, a hobby you'd rather not advertise, or a place where you argued more than you'd like. You want that one gone, and everything else exactly as it is.
That's a scalpel job, and the subreddit filter is the scalpel.
Scope to the subreddit
Filter by subreddit and the entire preview collapses to just that community - every post and comment you've made there, nothing from anywhere else. The live count tells you exactly how deep your history in that one place runs.
One sub in the filter, and the rest of your account disappears from view.
Layer in the other filters
Scoped to the sub, you can still be precise. Layer on a date range to clear only a particular era within it, or a score bound to target just the comments that landed badly. The filters stack, so "everything I posted in r/example before 2021 below zero karma" is one selection.
Or don't layer anything, and take the whole sub. Both are valid - the point is you decide the depth.
Keep the exceptions
Even in a sub you're clearing, there's often one comment worth keeping - the genuinely helpful answer, the thread you're proud of. Whitelist it and it survives the scoped sweep like any other protected item.
Run it, and that community is gone from your profile while everything else stays exactly where it was. Repeat for the next sub whenever you like.