This is obviously crazy talk, but so is keeping feature branches alive over extended periods of time. Depending on the development tempo of your project and the number of people involved, you should figure out a way to land things into main (in pieces if needed) within a few days.
I had created a feature branch before leaving my previous company, completed the feature and uploaded a build for testing, after which it was supposed to be merged.
Months passed and it has still been neither merged nor rejected.