Adopt storage on Samsung Tab S6 - do migrate step from terminal

Question

I tried using my sd card as internal storage on my Samsung Galaxy Tab S6 using this guide. But in the gui there is no option to "Migrate data", so I cannot do the last step.

It still worked in the sense that I can move apps to the SD card and they work. When I go to the Anroid system settings I get 150GB of 640GB used (i.e. total on both) and if I select the SD card I get the option to format as portable storage, so it's definitely recognized as adopted storage.

But the Samsung file manager now doesn't work anymore (keeps crashing immediately after launch, never displays) and the shared storage is still only the internal storage, i.e.

$ df -h
Filesystem                             Size  Used Avail Use% Mounted on
/dev/root                              5.8G  4.7G  1.1G  82% /
tmpfs                                  2.4G  1.5M  2.4G   1% /dev
tmpfs                                  2.4G     0  2.4G   0% /mnt
tmpfs                                  2.4G     0  2.4G   0% /mnt/secure
/dev/block/dm-3                        477G  4.1G  473G   1% /mnt/expand/64d7c406-5e2c-40e8-9cb9-b96d10aff34a
/dev/block/dm-1                        969M  855M  113M  89% /product
/dev/block/dm-2                        1.2G  1.0G  206M  84% /vendor
/dev/block/bootdevice/by-name/dsp       59M   28M   31M  48% /vendor/dsp
/dev/block/bootdevice/by-name/cache    390M  8.7M  381M   3% /cache
/dev/block/bootdevice/by-name/sec_efs   16M  1.0M   15M   7% /efs
/dev/block/bootdevice/by-name/userdata 110G   94G   16G  86% /data
/data/media                            110G   94G   16G  86% /storage/emulated

And I can't access /mnt/expand/*, permission denied.

Any ideas how to fix, i.e. probably run the migrate step from terminal somehow?