I've forked an app I use myself to add what I thought would be a (relatively) small fix. I then realised it was sort of left in the middle of a redesign/rewrite caused by dependency updates changing / breaking things and decided I needed to finish that if I wanted to see my code on a release. Along the way I got carried away and now the fork feels too large to pull request.

The changes I made don't meaningfully change the app structure but they required multiple refactorings/rewrites and extrapolation of what the redesign was trying to do.

The original developer is active but haven't committed to the repo in a long time. What should I do? I just want people to use the code I wrote. Do I PR and see what they say? Do I make another branch of its main and try to add my changes in more digestible chunks? Do I change the package name and release a build myself? I don't want to figure out a new name / logo etc, especially since the app is largely the same.

There are issues on the original repo about bugs I fixed. I'd like to point them to my fork, but that feels like shilling an unnecessarily made fork. And it doesn't feel right to drop a huge PR on the dev and expect them to accept it or even reply neither.

What do?