Mechatronic replacement vs full rebuild, how do I know which one I actually need?

Been nursing my 2014 A4 for a while now and the gearbox has started throwing a warning on the dash every few days, something about transmission malfunction but it clears if I restart the car. Took it to two different places and got two completely different opinions, one guy says just the mechatronic unit needs swapping out which he quoted around five thousand, the other garage insists the clutch packs are worn too and I should do a full rebuild while it’s opened up. I’m honestly lost because both sound convincing in their own way and I don’t have the technical knowledge to know who’s being straight with me. I did some late night googling and came across http:auditransmissionrepair.ae where they explain the difference between mechatronic issues and mechanical wear, finally feel like I have a slightly better grasp on things but still uncertain how to proceed when the symptoms could point to either problem. Anyone else been stuck in this limbo of not knowing whether to go for the smaller fix or just commit to the big job, and what ended up being the right call for you?