Well done with perservering.
I agree with the above, that particular trainer is not right for your horse. Nothing wrong with working outside your comfort zone occasionally but horses generally are not good at it.
If you have a formula that works, don't change it. If you feel you need instruction / encouragement please find someone who shares the same training methods as you.
He sounds like a terrific horse just a sensitive one that had got sour and lost his confidence.
You will never please everyone so ride him in a way that works for him even if it involves some less than classical riding - so what. Riding is (or should be) about have a safe, fun time.
Only As Old As You Feel - Sometimes I Feel VERY Old