Hi, I do not know if this will help but I had the same issue with transferring the data from Twitter. I had the transfer set to Twitter somewhere in 2019 until present time but 2019 I had it set on a google account. When I tried transfer the data from Twitter, natuarry didn't work but then I tried to transfer it from the same google account transfered back in 2018 and it worked. It turn out that the data can be transferred from all the accounts you set it even if this is not last one that was set for transfer. If you do not remove that data from Google or Twitter it will still stay there. Basically you can restore the game data from all accounts where you store it, doesn't matter in which the data was stored last. I hope this new fining will help some of you to recover your account.
Off course that this will help with recovering the data using play store game but it will still help since in 24 h you set set the transfer to a bandai account and try again with this mode.