I would check what fall you have inside the shower before you do too much more, Hobs are placed to get enough fall, removing it may cause more problems and result in a complete rebuild.
Most shower hobs are made of Hebel stone, an aerated cement, not too hard to chip out or get tile off.
However, if you remove the hob you will have to replace with a water-stop angle to prevent water running under the existing tiles and into your floor area.
Removing the hob will also damage the waterproofing and it will have to be repaired as well or you will have a leaking shower. This be possible by just removing the first row of tiles behind the hob.
By the ay, hobs are normally placed (or cast) on the floor, not on the tiles.
Good luck.![]()