I think most folks, namely webcomic creators, that do use youtube are the ones who are able to make longform content like those behind the scenes videos or speedpaints and on the fan side reviews but with younger audiences or those nlooking for more short form content then they take to places like tiktok instagram and twitter where tiktok is more short reviews or memes about updates or edits of their favorite characters and similar formats on instagram where discussion and hype is what seems to be happening on twitter
granted with twitter being in the weird state it is (along with a lot of social media in general really) the flow of activity and this potential for success is really in flux so i'd imagine it'd probably be easier to get a foot in the door if you've already got a sizeable following for your work, otherwise a lot more time will be spent on building up that platform alongside posting updates or whatever else
personally i follow most comic folks on twitter coz that's been the easiest one to navigate and use along with tumblr tho that one has been more geared to different styles of original content and fancomics but they've still been effective for following folks and keeping an eye on certain discussions here n there
as for newer places folks flock to beyond those the only one that comes to mind is bluesky or neocities but whose gone where depends on age and preference for online spaces/interactions since bsky is twitter clone while neocities is more old web. there's probably more than even that but those are ones i'm actively aware of or can think of
