And to add to that -- word of mouth. Sometimes, there are people who prefer to find creators not through your standard social media, but through other socials like physical ads, newspapers, and even just talking to someone in passing.
And word of mouth can be a lot of things too! For me, "word or mouth" is just drawing something for a class project or something when I'm a part of any campus programs. I was part of a leader program for my university and I did a bit of drawing for this group I was leading. They asked if I did any work online, and I pointed them to my webcomics. Turns out a few of them were already reading my works!
Sometimes, it does call for talking to actual people to advertise, so I like to mix it up and do stuff both online and in person.
And I do feel actually interacting with your readers and others helps build your rep than just posting on the social medias and not...talking? Like, I see it here in the forums, in the discords, and elsewhere. People just post their work but don't talk, and they kinda expect someone to see them. Problem is -- they're in a sea with many other people who post their work and don't talk. And after a while, you just become invisible.
Edit: And another thing to add -- study the genres you do and don't work in. I see a lot of people who go "well, I don't read romance" or "well, I don't work in action". Even when something is "popular and mainstream", people choose to not at least peek and see the "why" and the "how". That's limiting.
Even though certain genres may have certain tropes they're known for, all tropes and ideas overlap the genres. It's why we get romance horror or drama comedy. And even if we don't like something personally, objectively, we can find a way to look at it and go "ok, I think I understand why it's doing so well".
As creators, it helps to consume ALL media at least once or peek over and go "hmm, I wonder what ideas and themes they're using". It doesn't mean you copy panel by panel, word by word, what a famous creator does because, full harshness, you are not that creator; you won't be able to do the themes the way THEY did it.
You can only do the themes they use YOUR way, and that's the point. To be able to look at the themes other people used for their works, consume it, and go "ok, what do I like about these themes? How can I use them? Do I want and/or need to use them?" When you consume media, any media, you are able to find ideas and twist them in your own way or go "but what if it was like this way?". That's part of marketing and drawing in other people. Sometimes, you gotta start with what you like and what you dislike and just...look at stuff objectively.