Decided I will not be using posts, but only notes. This way I can make use of the wikilinks throughout all notes and have them also show up in the RSS feed.
For this I added a custom feed.xml file, and changed the feed: hide/show property to feed: false/true.
Now I can also have just the _notes folder open in the Obsidian vault as I'll be doing all my writing in there. If I want to add a page, I will just have to move it manually – but here it's also good to consider if a page is needed, or whether I can just use notes?
Just came across a new error regarding the link above: I cannot use a different display text right now. How to write wikilinks with alternative display text?