Apologies for being extremely busy and not assisting with Gramps lately. In the last few years I have accepted many PRs for Addons and built/released them. Since i have been busy, this has fallen by the wayside.
I still think that using the PR system is the right way to submit changes to addons. It may help in a few cases to contact the author of the addon as well. For instance, I have not dealt with changes to the Forms addon since that was originally written by Nick, and I don’t want to cause trouble there.
If the original author has tested and accepts (via comment) the concept of the PR change, it saves time for the developer (me?) when it comes to doing the release. Note that the release process bumps up the version number and this results in a commit, so it is usually better to NOT commit the PR if not doing the release; it would add extra minor commits to the history.