How can I make this work:

ssh admin@192.168.88.1 < myscript

or

(sleep 1; cat myscript) | ssh admin@192.168.88.1

or

(sleep 1; echo; sleep 1; cat myscript) | telnet -l admin 192.168.88.1

somehow these don't work. What is the proper way of executing a local->mikrotik script, without making a script on mikrotik itself.

Yes, I read the readme.