I am looking to switch careers from Software Engineering to Mobile developer to work as a freelance in exciting projects. I am wondering which mobile tech is best: Android or IOs or Flutter?

I do have knowledge of Python, Sql and a bit of Javascript plus data engineering. So I should not be taking more than 6 months to become confident with it. Do you recommend first to learn and make 1 app as a portfolio to show to agencies and recruiters?

I am based in the Netherlands so I am looking for projects based in Europe time zone.

Any advice, steps recommendations greatly appreciated!:))