ludvigzg Hello,
You can check the list of our templates that have J2Store support here.
However the last version of J2Store we've tested with our templates was v3.3.17 so they might not work well with the latest J2Store version for J4.
In order to migrate to Joomla 4, please make sure all your templates and extension are compatible with Joomla 4 first, then follow the guide from Joomla.