You’ll need to disable cross save then run through the setup again. There’s a 90day timeout though. I need to ask, how did you get it wrong ? Crossplay setup shows the accounts, asks you to select one then displays that platform, states “You have chosen *insertplatformname* to be your Active Characters. With a confirmation button underneath. Then goes to a new confirmation screen that shows the selected platform will be playable on the other platforms. Lists the licenses owned per platform with ‘Back’ and ‘Yes. Do It’ buttons. This is then followed by another confirmation screen stating amongst other things that there is an [b]unskippable 90 day wait period [/b] related to deactivating/reactivating cross save. I don’t think they could make it any clearer.

After the mandatory 90 day lock out yes you can.

Sure, after you unlink the incorrect one, wait 90 days and then do it again.