SEO question: H2 vs H3 headings?

I’m trying to enhance my blog posts and have gotten advice that SEO/GEO likes H2 subheadings. (I use H1 for my blog title). However, my blog posts are fairly short (under 300 words) and the H2 subtitles seem too big and overwhelming. Am I handcuffing the SEO if I use H3, which I think looks better for formatting?