Hey you might want to get one of those suction non slip mats for children to go in the bottom of the bath. Half the reason my dog hated baths was because it was slippery and he felt unsafe (he's also a large dog). As soon as I put one of those mats in and he could stand normally, he realised it wasn't a big deal and started getting in the bath begrudgingly but voluntarily.
This is genius. Gonna do this for my boy next bath. He hates them, he constantly tries to climb out, and the peanut butter on the wall thing doesn't work.
My little dude is perfectly calm in the tub... So long as I get in with him.
I wish mine had a bar like that I could leash them to. My husky is too big to be in the tub with and she doesn't like baths either (despite loving water literally any other time 😔).
You could try something like this. I haven't used those but the bar does help a bunch. That, plus one hand constantly on their heads to keep them from shaking the soapy water off before it's time made a big difference. And lots of treats to expect afterwards. My dogs are fine once they're in there and wet, they just want to do everything possible to avoid it beforehand -- and who can blame them.