I can’t imagine just opening a giant PR without having extensive contact and coordination with the maintainer. Almost any amount of incremental safe steps would be preferable to a giant PR, even with extensive communication. I once introduced fully strict typescript into a vanilla js codebase and it took dozens of small PRs to do so. It was made more complicated by the fact that it was a library, but still. The communication made the entire process smooth and let everyone be confident the changes were correct along the way. If I’d done it all at once without any coordination, it would have been faster for me, but at the cost of the maintainer’s sanity and time.