At 500 followers, the move is to stop thinking like a product page and start thinking like a community page for gym girls. People don't follow brands on Instagram because they want to see products. They follow because the content makes them feel something.
Some ideas that tend to work well in this niche: workout tutorials using your products (like showing ankle strap exercises with proper form), gym outfit inspo where your accessories are styled naturally, relatable gym memes or "gym girl problems" content, and user generated content from customers actually wearing your stuff. That last one is huge because it builds social proof and it's content you don't have to create yourself.
For Reels specifically, try quick "get ready for the gym with me" style videos or "what's in my gym bag" featuring your products. Keep the vibe aspirational but approachable. The aesthetic look is great, just make sure you're mixing in content that people actually want to share with their friends, not just scroll past.