Whether private members should affect PEP 695's type-var variance

You can achieve this by declaring K and V manually with the variance you want. auto variance should be safe by default, if you want to do unsafe things, then you have to be explicit, I don’t think that is too much to ask. PEP695 was supposed to be a simplification for the most common cases, it was never intended to replace manually specifying TypeVar variance entirely, since that is not possible.