[gentoo-user] Again some "headless" stuff/question

Hi,

for starting and running a script on a headless system for me "nohup"
works perfectly.
For interactive session via ssh screen/tmux turned out to be the
solution to detach from jobs started from the commandline.
Both are hints/help I received from the community here. :)
Thank you very much !!! :)))

Since the screen/tmux thingie is THAT convenient I would like to start
this as the default when logging in via ssh.
I could write a script which is started by the shell (zsh) which in 
turn is started as part of the login process.
Screen would start another shell and TADA!...
But this is an embedded system...

The result should be a running screen session right after login via
ssh.

Is there any "shorter path" to what I am trying to do -- without the
cascade of shells which do nothing but waiting of the child process to
end?

Thank you very much in advance for any help! Have a nice Sunday!

Best regards,
mcc