Chosen Solution
I’ve got no external video in my MBA Early 2015. I’m running last Big Sur update. Monitor and cables are working. Reinstalled OS, from El Capitain to Big Sur. Reseted smc, but no monitor image.
Not good ;-{ the Thunderbolt port logic has a people on the main logic board. You’ll either need to find someone with the deeper skills to fix your logic board or you’ll need to replace it. MacBook Air 13" Early 2015 Logic Board Replacement
