MI is stock ROM for All country/nternational country/Global rom/Multilanguage, IN just for India country, EEA just for Europe region, RU just for Russia country, ID just for indonesia country and CN is Chinese rom or factory firmware and just EN (English), CN (Chinese) Which can be flashed to all phones in any region but not multilanguage and no included Google playstore Q is Operation System or Android 10 Q version
For unbricking, Software update, Repair firmware, fix unknown baseband or IMEI, unrooting, Switching from China stock rom to global stock rom, Global stock rom to China rom, Develover rom to global stock rom, Beta rom to stable version rom, etc.