In a nutshell, my Nintendo account used an old email that is now deleted, so I’m unable to reset my password. I have contacted support about this, but apparently my account does not exist? (Perhaps, due to the non-functional email, my account is no longer on Nintendo’s servers while the game data is still available locally. And indeed, trying to access the eShop does not work)

I am still able to play my games while retaining game data, but it’s essentially locked in my old Switch, since my account is inaccessible. Is it possible to transfer game data between my old Nintendo account to a new one, or alternatively, transferring game data to a (Linux) computer to be used in an emulator or something?

Another question, if I was to reset the system memory while moving most of my game data to a microSD card that I remove beforehand, could I transfer my game data like that, or is there Nintendo proprietary nonsense requiring the correct account/user to access that game data?