Dropbox backup type error - Illuminate Filesystem expected, League Flysystem given

[janzikmund]

laravel/framework: 9.19.0
spatie/laravel-backup: 8.1.2
spatie/flysystem-dropbox: 2.0.6

Hi, I recently upgraded to the versions above from Laravel 8, laravel-backup 6.14 and flysystem-dropbox 1.2.3. I have dropbox mapped as Laravel disk using Flysystem adapter as per Feek's blog here.

But after the upgrade, all calls like php artisan backup:run or php artisan backup:clean just give me the following error:

Spatie\Backup\BackupDestination\BackupDestination::__construct(): Argument #1 ($disk) must be of type ?Illuminate\Contracts\Filesystem\Filesystem, League\Flysystem\Filesystem given, called in /Users/ziki/Sites/mysite/vendor/spatie/laravel-backup/src/BackupDestination/BackupDestination.php on line 60

I tried removing /vendor dir and reinstalling composer dependencies, it was the same. I also tried downgrading backup and dropbox packages, but the older versions don't really work with Laravel 9.
I even tried changing the typehints to avoid the mismatch, but then I got a number of errors about methods not defined, so I am kind of stuck here and wondering if Dropbox can even be used this way anymore?