@oeyoews
I use the autocomplete plugin from @Maurycy. There is a well-developed set of triggers from community (see for example Community Curated AutoComplete Triggers - Tips & Tricks - Talk TW (tiddlywiki.org)). Furthermore, the autocomplete works in fields other than text, so I like to keep both plugins autocomplete and codemirror6.
Are they compatible? My emphasis is on the autocomplete feature of Codemirror6.