Best advice for this case?

I'm in the art niche (promoting myself as an artist) and I've found really interesting tips here but some of them doesn't apply in my case. For example I can't mass follow unfollow because that would hurt my online presence as an artist creating myself a bad name, I can't update 2-3 times a day because I make all my artwork and I just don't have enough time for creating that many pieces.
I can't buy an already grown account because I already have some following in mine.

So any advices in this particular case? I'm kind of stuck.

Follow manually people that are interested in art. Create a blog if you don't have one already and post images of your work stage by stage as you create it.

If you want to go a little black hat then create some "fan" accounts on social media and do follow unfollow with those whilst using them to promote your primary account(s).

Buying shoutouts from other artists/pages seems the best option for you. This way you'll have people following you that are sincerely interested in your work.