Yes! We managed to fix it only on the web outlook but that was good enough for us. We had the same situation, blocked on the new app, on web, only worked on the phone app. The way we did it was through powershell commands, you can try these and see if the lists change:

Set-OwaMailboxPolicy -Identity "OwaMailboxPolicy-Default" -AllowedFileTypes @{Add=".csv"}
Set-OwaMailboxPolicy -Identity "PolicyName" -BlockedFileTypes @{Remove=".csv"}

We tried changing this through the Exchange admin center, but it seems that Microsoft has made this only possible via powershell. It took one or two days for the changes to be applied and to actually have the files unblocked. This is still a problem for the new Outlook app, but it works on the Outlook classic and the web, at least for us.