There are two parts to this answer. If you flash an official firmware from another country, as long as its the same model then you will be able to run that firmware without trouble. However an initial flash often doesn't change the CSC code of your device, it often takes you to after initial booting of new firmware, go into recovery, wipe cache partition and then do a factory reset / restore once more.
Forcing it to re-do a factory restore and wiping cache partition will align the firmware you are flashing and the CSC (the country identifier) together.
If they are aligned then you will be able to restore in smart switch in future, BUT ... it will of course be of that new firmware country that will be restored.
IF CSC and firmware are not aligned, then you likely wont be able to restore in smart switch and OTA updates may not work.
If you want your original country firmware and CSC - the only recourse is to wait until its available. Do you know what the CSC of your device currently is ?
Download "phone info for samsung" from the google play store and run it to confirm what CSC your device currently has please and post it here.