Is selective merging possible in HG?

Question

Version control systems

I am developing a fork of one product in PHP.
All changes are fixed by the Mercurial version control system.
A new version of the original product comes out, and then another...
What is the best way to combine my supplements with the new version when there are a lot of changes?
I merge minor releases simply, all at once, but major ones differ much more seriously, and I will drown in edits.
You can merge not with the head of my branch, but with, for example, the middle, but here the question arises with bug fixes.
For example, I fixed a new feature in commit 10, and fixed it in commit 100.
But when merging with a new major version, I would like to test the resulting code, but testing it with known bugs is somehow not right.
So I would like to merge first commits 10 and 100, and then 11-99, and so on.
Is it possible to?
There was an idea to put each function in a separate branch, and commit the fixes to it, well, and merge it, and not the branch with my previous version, but again, this will only help with the first major release, since if bug fixes were made after, then again we come to the need for a selective merge.
I apologize in advance if the description is not clear.