M.M.
Hi N.,
I would suggest you ditch the inflatable tub and put her in the regular tub with a little less water. The infaltable tub with water in it could feel really unsettling to her since it probably moves when she moves, and the other tub- a hard plastic bowl essentially didn't. Give her the solid tub to feel safe in. I'd put a mat on the bottom of the tub so she doesn't slide around and see what happens.
I never put my kids in anything but the regular tub after we gave up on the infant tub. They get to add bubbles and raise the level of the water or let it out - draw or just splash around as they want.
We went through a "i don't like bath phase" too, but that was around 20-24 months, when washing hair was the struggle.
best,
M.