Looks like a really cool product addressing a real pain. Anyone who has been around for a while has been affected by what you describe, the first few copy paragraph are really good in that regard. However, I feel like your h1 does not really encapsulate those benefits well, it's too generic.

Here is a good AI generated summary of your core USPs: "Buttondown is a reliable, creator-focused email platform that prioritizes simplicity, customer feedback, and long-term commitment. It offers powerful automation and personalization features without the complexity, bloat, or hidden costs often found in other platforms. Buttondown is designed to be dependable, transparent, and user-friendly, making it the last email platform you'll ever need."

And here is an H1 that I think works better for those USPs. "Email That Just Works – Simple, Reliable, and Built for You"

Best of success and excuse the unsolicited advise.