On the other hand, there's been an endless parade of recent posts from other FOSS maintainers saying "we don't want your drive-by PRs": it's not hard to see people getting dissuaded from the whole dance of determining whether a project is receptive at all, then whether it has a reasonable number of hoops for outsiders to jump through.
Now, personally, when I file a bug report for a FOSS project I like to suggest an underlying cause and fix if I can figure it out, but I more rarely just submit a PR outright.
If I have to choose between no PR and a "drive-by PR" where the author doesn't understand the changes to have a discussion, or isn't available to do changes and expects me to "take it from there", then I'd much rather go with "no PR" for the sake of everyone.
Now, personally, when I file a bug report for a FOSS project I like to suggest an underlying cause and fix if I can figure it out, but I more rarely just submit a PR outright.