I know this post is old, but maybe it will help someone, although I have a fairly short response:
Pain can cause much fatigue. It's very common.
In addition, it sounded like long COVID might have been involved, which can exacerbate fatigue.
Finally, you mentioned you had mild fatigue prior the surgery. If your fatigue was related in any way to fibromyalgia, chronic fatigue, long Covid, etc., it is very possible that these things will also increase your recovery time post surgery.
I surely hope by now you are doing better. (I came here because I had oral surgery today!)