I would say if you want them to be a nice summer road wheelset then go for 21mm internal. They'll work well with 28 or 30mm tires and I don't think you'll ever (never say never) want bigger than that on a nice summer wheel.
If down the line you want gravel wheels then hopefully you'll have saved some money for something a bit burlier which you won't mind dragging through SFAB.
I would say if you want them to be a nice summer road wheelset then go for 21mm internal. They'll work well with 28 or 30mm tires and I don't think you'll ever (never say never) want bigger than that on a nice summer wheel.
If down the line you want gravel wheels then hopefully you'll have saved some money for something a bit burlier which you won't mind dragging through SFAB.