Because of this error http://myserver.local:22300/api/sessions failed, reason: connect EBADF 192.168.0.10:22300 (Code EBADF) I assume, your server is on the IP 192.168.0.10, right?

So as you type in your browser 192.168.0.10:22300/api/sessions you get error "Not allowed: GET api/sessions"?
And when you type in 192.168.0.10:22300/api/ping, do you get an ok and Joplin Server is running?

If so, the configuration should be alright. I would check the authentication credentials again. I don't know, what else could be the problem, as I tried to reproduce your setup and it worked out for me.

No, the Server does not need to run on https, however it is strongly recommended, if you don't use it in you local network only.