Welcome to our community and thank you for your question!
It's true that you are allowed to stay in another EU country for a maximum of 90 days within half a year. But you are not allowed to work there.
It's hard to move within EU because your residence permit is only valid in the country that issued it. If there are convincings reasons why you want to move (e.g. because you married a citizen of the country you want to move to) you can get in contact with the embassy of said country and ask for an exemption. You can also contact them to find out if there are other options to move.