Not being familiar with a part of a codebase is not an incurable condition.

If the conclusion you made of that there is no workaround, then let that be the entire point. The alternatives are to get over yourself and ask people to implement a feature, or to understand how to help and then help.

The former is what OP did; the latter I described what I see as an efficient way of achieving while making use of an LLM-produced PR.