Wait, by “fine-tuning”… do you mean LoRAs? Because those are more like brain surgery with a sledgehammer, rather the opposite of “fine”. I don’t think it’s possible for LoRAs to avoid having undesirable side effects… and I don’t think people even want that.
Actual “fine” tuning, would be adding the LoRA’s training data to the original set, then training the whole model from scratch… and that would require increasing the model’s size to encode the increased amount of data for the same output quality.