packages held back

[diederik]

I ended up runnig apt install mobian-base mobian-phone-base mobian-phosh-base mobian-phosh-phone.
As far as I remeber it's safe than full-upgrade when running testting and sid.

FYI: No, that doesn't matter.

If you have enabled both Testing and Sid and not configured 'other' things, then you're actually running Sid.

What often happens when both get enabled, is that Testing is made the default. Run "apt-config dump | grep Default" to see if that's the case.
When Testing is the default, then you do things 'in' Testing, unless you explicitly specify otherwise (via f.e. "-t sid").

APT selects the package/version whose priority is the highest and if the priority is the same, then it takes the highest version.
When you set Testing as Default-Release, then Testing gets a priority of 990 vs the standard of 500 (for Sid).
See "apt-cache policy" for the general settings and "apt-cache policy <pkg>" for a specific package.

I am only running trixie. I meant in general if one is running testing or sid.

The only time that "full-upgrade" is 'dangerous' is if you use the "-y" flag and/or don't read or ignore what APT is telling you it's about to do.
If APT is telling you it's about to remove 90% of your system and you don't want that, just say 'No' to abort.

IMO you should ONLY use "-y" when you're scripting and I think that (generally speaking) scripting system updates/upgrades it rarely a good idea.
Just do it interactively at the prompt and read what APT tells you and then use your common sense.