That's a smart approach honestly, frequent small updates keep things feeling alive without the pressure of a big reveal every time, and clever that you built your own tools to make content additions easier early on, that's going to save you a lot of time long term.
For free early access platforms, itch is honestly already one of the strongest for that kind of iterative, community-driven approach. One other option worth considering though is YouTube Playables, it's a newer platform where browser games get embedded directly into YouTube and surfaced to a huge built-in audience without needing to drive traffic yourself. Since you're not doing Steam early access, that could actually be a great fit for getting more eyes on the game while you keep refining it. If that's something you're curious about, it's actually an area I can help with, happy to walk you through how it could work for your game specifically.