Chinese hamsters can be very timid & some are slow to tame so the key is just patience.
I wouldn’t put a Chinese hamster in the bath for taming I think they would probably find that quite scary really.
I would slow right down & maybe not try to take him out of his cage for a little while yet.
Spend lots of time just being around the cage talking to him to start with, let him get really familiar with you being around him.
Getting them used to hands can take some time, some are quicker than others, try putting your hand flat in the cage, close to the door if it’s a cage. not a tank but well away from any burrow holes, keep it still & flat with a treat on & if he won’t come to you at first just wait a while then remove your hand & leave the treat there for him.
I wouldn’t wear gloves with a Chinese, they rarely bite at all & only if quite scared so gloves wouldn’t help him get used to you & might make him even more nervous.
Doing that should help him realise your hand means good things & isn’t a threat.
I wouldn’t try to move forward with taming until he’s a bit more comfortable with your hand.
When he is do try a playpen with lots of toys, hideouts & a wheel but not too much open space in there. To begin with just sit & talk to him & let him run around, keep sessions short & gradually try to begin interacting with him.
Do you have a photo of your cage set up? The. set up can make a big difference to how secure & confident they feel so it’s possible there could be some changes you could make that might help.