Regrettably if warranty terms were respected there’s not much you can do from a legal point of view, besides contacting the dealer and appeal to their good will. I’d feel miserable if my repair on a Mac would fail 95 days after working on it and try to find an acceptable solution for both parts. However, if you are denied an acceptable arrangement for you, the only reasonable advice I would give is to try and find an indipendent reputable lab into component level repairs, some work on a no fix no fee basis and may be able to repair your Mac for a fraction of the cost of a board replacement.