Bad_forest_monkey says:
And lastly is there a max on the ac buffing I can do, because if I get my plate mail back in think I'll be at 21ac
Yes, there is a mechanical maximum. For example, if you end up wearing full plate (which you shouldn't have had to start, I think pallies only get chain to start. full plate is like 1500 gold), you end up being at 18 AC. If you add a shield to it, you go to 20. If you go Defense style, it goes up to 21.
Beyond that, there are some magical items that would provide you with some additional bonuses on top of that.
And a 21 AC is perfectly fine. Partially because you won't realistically be sneaking anywhere with that get up on. And it's also one of the reasons (mixed with lay on hands) that pallies are some of the best damage soaking tanks out there in 5e.