Years ago I had an issue with VSCode: it was missing a small feature that was very important to me, with the GitHub issue stuck in limbo.
I ended up going into the source and implementing the feature myself. It took a few hours after bugfixing, I think the fix was ~100 LOC. Then I used the locally-built version. I recall building took a while, and the source and artifacts took a lot of space, but no other problems.
I also created a PR referencing the issue and it got merged rather quickly. Someone else ended up finishing the work since there were some problems (I think relating to coding conventions, and possible edge cases I didn’t need or handle).
Maybe I was lucky for the feature to not require much edits, and probably for the PR to get taken over and then merged fast. But it seems like the author's issues are also small, and it would be easier and more ergonomic to patch VSCode than to create an entirely new debugger.