If the shower floor is leaking, the shower will usually have to be redone. Then you can put in the tub you want, too. Have you hired a professional bathroom designer? Have you moved in already?

I am far from a pro, but doubt it’s possible to successfully just replace the floor in a shower and still have a trustworthy waterproof surface. And if the tub is to be changed to freestanding, that wall of the shower would need to be reworked, wouldn’t it? I would guess the shower and tub would need to be taken down and that area redone to accommodate a freestanding tub and shower. Maybe make that whole space a wet area. Looks pretty nice as-is, in my opinion. Good luck!

Why are you changing everything? the yellow? What a terribile waste. How long have you lived here? This bathroom is beautiful and tasteful. Yellow doesnt seem a good enough reason to bring on the sledgehammer :(

Change the bulbs in all your lighting to daylight LEDs in the 3500- 5000K range then see what the counter looks like. You do not have space for a freestanding tub unless you give up something like the shower. IMO corner tubs are a PITA to clean so unless you love to bathe get rid of it alltogether if you are going to gut this space if not leave it alone. I am not a lover of over the top huge bathrooms but this one seems quite nicely done.