My DS hated bath time too. Bathing together was a little better so i agree to try it, but for mine he still wasn't happy. So, I washed him with a cloth morning and night and dipped him in the quickest bath no more than once per week, maybe less tbh but he was clean and that's really all that matters. There is a life time ahead to learn to enjoy water, swimming, baths, etc it doesn't all have to happen right now. I treid a different type of bath time to time but not too frequently so as to respect his dislike. He was once happy for a couple of mins in a FULL bath with me holding him up, almost swimming/floating.
At about 5.5 or 6 months he suddenly enjoyed a bath if it was very shallow and he was laying down on his back in it (so shallow that it didn't not go past his ears when laying - dry face) and smiled at me. For a few months we did that, it was lovely and worth the wait. That's when we took a swim class. Then he didn't like laying in it any more and wanted to be sitting up but continued to enjoy having baths, every day. Once he was sitting up he couldn't bare water poured on his head (despite having previously been fine with it) so hair washing was difficult (I used a wash cloth and avoided pouring water for a good while so that he did not become frightened) but eventually he has learned how to tilt his head back and accepts water on his head.