I empathise! I used to enjoy a long soak in the bath, topping up the hot water every now and then - until we had the bathroom refurbished 15 years ago! We splashed out (pardon the pun) and got nice stuff. The bath is a Laufen and that alone was about £1,200. But we've hardly used it.
The first time I used the new bath I realised that it was completely wrong for me. It's basically far too big (maybe we should swap, OP!). It's very deep and wide and is longer than the old one. It also has a steep slope on both ends (the tap is in the middle, on the wall).
When I try to lie back in the bath, I just slide down the slope (it's incredibly slippery!) - and because it's so long my feet don't reach the end, so I can't stop myself from sliding down under the water! I bought two bath pillows - one for my head and one to brace my feet against, but that doesn't really work. I bought a full length non-slip mat to stop me sliding, but the slope is so steep that I still slide down the mat!
Both DH and I gave up using the bath years ago, so it sits there gathering dust and the ocasional spider takes up residence!
My big mistake was not to actually get into the bath in the showroom and try it for size. If I ever refurbish another bathroom (doubtful, I think we're stuck with this one) I shall get into the bath and lie down in it in the showroom, regardless of what anyone might think!
I've got totally used to always having showers now though, so I doubt I would ever take up bathing again.