> breaking the standards of the project lead to higher mental load to maintain that code over the long term.
Nah. Over the long term the lava layer pattern is the only way to stop the mental load of the project from growing indefinitely. You will ultimately have to keep up with modern development practices, because keeping everything on standards from 2010 will ultimately be even worse, and the longer you leave your migrations the more painful they will be.
You don't and can't fully replace each layer, at least not in order - you should expect to have three or four ways of doing things in the codebase, that's just the reality of large old codebases. It still beats having your whole codebase be stuck on the oldest of those three or four ways.
Nah. Over the long term the lava layer pattern is the only way to stop the mental load of the project from growing indefinitely. You will ultimately have to keep up with modern development practices, because keeping everything on standards from 2010 will ultimately be even worse, and the longer you leave your migrations the more painful they will be.