I would listen to all the advise given already but I’ll toss in my experience though it may not be useful or relevant to most people!!!
By and large the best growth for me has always been when I lean more into comedy and strips. Even when I’m not actively working on a strip I will promote my comics by isolating a panel from the comic that I think would be funny enough for strangers to want to share with their friends with no context.
Social media is all essentially word of mouth so its worth thinking about what would get people to SHARE something and I think this advice is applicable to a lot of webcomics folk because 9 outta 10 times when I go to a webcomic creator’s social media there page is content to notify the readers they already have but not content that would hook a new reader or attract sharing and interaction. And this is can look different from creator to creator. For me, its comedy.
I’m at 75.5k on IG now because I started a warm up comedic slice of life strip that I do before I do my graphic novel work. I put more effort into it than I honestly intended to and because if that strip my Twitter went from 2k to 22k in a couple months. It is Very Sharable content and it funnels a ton of readers into my more ambitious/“serious” work so its worth it for me in the end. I don’t use hashtags, make fanart, I’ve never done a DTIYS, or buy ads, I just actively make things with the intent of having people WANT to share them and practiced with a ton of trial and error along the way.
Obviously, this isn’t advice for everyone! Not everyone wants to do this or want to take the time to hone their comedy writing and that’s perfectly fine but I like sharing my experience and what works for me and hope its something that someone would find interesting and potentially useful!