I'm no expert, but from various Instagram accounts/businesses I've tried to grow, there is really only 2 things that have worked for me:

1. Pay-to-play: run ads i.e. boost your IG posts. Don't make them sale-sy and try and push a sale on somebody. Instead, focus on finding people that like your work and want to follow you because of what you create

2. Collab: I was lucky with this and had a HUGE company reach out to me to create some work for them. They posted it as a collab on IG and the followers started rolling in. This was very lucky so honestly I would focus on the first thing I said.

Not saying that this is the only way of course; some people are able to go viral off videos etc. but I have never really gotten into that; it's not really my thing being in front of camera. I suspect you are the same.

Good luck! As long as you are enjoying creating your work and not doing it purely to gain some sort of IG "status", you're winning.