I've noticed that I often have conflicts in backports_required_for_multiversion_tests.yml, because many add new entries at the same place - at the end of the list.

An easy (though imperfect) improvement would be to randomize the position to have less probability of the conflict.

I'd suggest to implement this solution as a python script, e.g.,

buildscripts/multiversionRequireBackport.py [--lastLTS] [--lastContinuous] <jstests/path/to/test.js> <SERVER-ticket-number> 

No optional arguments would mean both lists are modified (default).