Height differences in different rooms

What flooring have you had experience with in bedrooms? What can you recommend? I’m having a hard time especially with the children's room.

Everything except tiles is okay in my opinion. It depends on your personal taste and budget.
Parquet was too expensive for the children's rooms for me, vinyl had too much plastic (bad plasticizers (let’s leave it open here whether that’s true or not)), so I went with a decent laminate.
There are also ones with, for example, 12mm thickness, so you have less difference in height compared to the tiles.