Well I'm probably not really in the target audience, so take my confusion with a grain of salt if those are widely used terms among those who are. The list of features in your other comment does sound pretty appealing though. Maybe the site should have something like that as a column down the side or something - I would have immediately understood instead of coming here and complaining about headlines!
I'd call it "stylable", "freely stylable", "add your own CSS", "DIY CSS" or similar, as they seem like they mean what you're talking about even to people who haven't run into them before.
Artisanal to me suggests obviously handmade and deliberately unpolished (as a stylistic choice, not a negative). The immediate image that sprang to mind was pottery with finger marks in it, so I was a bit lost with "web artisan". The strengths of tiptap seem to be the flexibility and customisability, and realtime collaboration, so a word that got that sort of thing across would communicate more.