Yamato has potential to be good... but also quite shit...
I like his design, I like his power too.
His Oden worship is no different than Luffy's worship of Roger or Ace's worship of Whitebeard. If you will banalize Yamato for having Oden's diary, a memento of her rolemodel, the man that embodies everything he missed in life when it came to parenting and overall life questions then do the same for Luffy and his Strawhat, Nami and Orange tree and so on.
If you father was Kaido, chances are you didn't have a nice childhood. So if your only parental thing was Oden's diary ofc you will have some weird shit going on in your life.
The only problem I see with Yamato is that He is stuck guarding Momo and that ruins his character. Give her something else to do, something to show her off better.
Right now Momo is the sole reason his characters suffers