I have had to change a bath for someone before and took it out without damage to the tiles by lowering bath first - but it is a real ball ache , only did it as tiles were discontinued
Could be a easy job , could be a horrible job
Could be pipes and electric going through old joist , bath could be screwed to wall , tiles could be well and truely stuck - if I was to price it then I would definitely cover myself
On the other hand , it could go like clockwork and be a breeze
I wish you good fortune 👍