It’s not that easy. To remove a pool you have to get a permit from the city that costs thousands and takes months just to get. Then you need a structural engineer to assess it more thousands. Then you have to have people come in remove all that water then fill in the pool which will cost you about 50k. My neighbor just had her pool removed out her back yard and cost her almost 100k. Inside a house is probably worse because you’re going to need to level and get all new floors to match.You can easily fill it with cement and tile it or laminate or whatever