@troed honestly, I found the process relatively easy and straightforward. I can help you if you have any specific issues. The signing thing is pretty much 4-5 commands you type once + a PR and you're good to go.
You can also look at my app template repo for inspiration on how to automate it:
GitHub - chenasraf/nextcloud-app-template
Contribute to chenasraf/nextcloud-app-template development by creating an account on GitHub.
GitHub (github.com)
Feel free to reply with questions if you need help 
always love to see the ecosystem growing