Maybe there is already a possibility to include mosh into the connections, like connecting to the localhost first and then hop further using a predefined command line involving mosh.
Unfortunately version 3.10.9 crashes on macOS Tahoe 26.1 on all intends of trying to configure a connection - so currently no way to figure this out.
This way you keep unstable connections, like being on the train, useable again for all purposes. And you still can use the environment you are working with every day. That would be a big effort.
Actually I could get that run on macOS already, steps on how to for those who are interested:
Create an ssh connection to 127.0.0.1 as usual
on the advanced tab scroll to the very bottom and enter into Post Command/Remote Command
"/usr/local/bin/mosh --ssh="ssh -p 22" user@DST-host.com", adjust user, host and ssh port to your needs of course, this makes your local machine execute the given command.
move your mosh script away and copy it back, so you can edit it (you will be the owner)
mv /usr/local/bin/mosh /usr/local/bin/mosh.bak
cp /usr/local/bin/mosh.bak /usr/local/bin/mosh
vim /usr/local/bin/mosh
search for and change the line and save the script
from: my $client = 'mosh-client';
to: my $client = '/usr/local/bin/mosh-client';
There is no guarantee it will work on your machine, but at least it did on mine.
Maybe there are easier ways too, but at least this worked for me. I could edit my profiles with the app store version 3.10.4 (which has only some of the failures built into 3.10.9), due to cloud sync the connections appear as well in my 3.10.9 version and are useable but not editable.