Hi @Verhoeckx ,
The Q4 is a bit technical. The developers could guide you on this. Sorry.
Q.5 – I think this will be possible in Block editor. Next release. Bert had asked a similar question in this thread: https://forum.getpublii.com/topic/publii-3-6-prerelease-1-ready-for-testing-come-help-us-make-it-better/
Q6 – Again I am not sure. I asked Bob once about creating mega menus similar to WordPress, and he said no. So, he might be able to answer this. Sorry.
Q8. Welcome 🙂