Hi @ssh !
For tagging inline, have a look at Inline Tag Navigator (works on mobile). It was inspired to some extent by Logseq. You may then view all tagged lines / paragraphs in a panel, or in a note that is dedicated to a saved search query (a single tag, or a more complex one).
For linking while creating pages, try Quick Links (works on mobile). You may enable in the settings the option to Allow new notes. You can combine this with Automatic backlinks. Ideally, you would want something like Bidirectional Links on mobile, but it's not enabled on mobile yet (I believe it should work, if @benlau is interested).