i realized i have to mark “ship to all countries” to make that “use all other countries as C4” button i was searching for appear.
however initially i had to use the workaround using “sell to specific countries” and then adding all countries to the box to make that work, that was the only workaround that made it possible to get the postage calculated.
so now i’m in a trap because if i use “all countries” calculation wown’t work at all, and if i use “specific countries” i can’t use the “use all other countries as C4” button…