Glad you're holding the "nothing leaves your machine" line. A lot of tools in adjacent categories added cloud sync early, the local audience didn't come back. If you can keep v1 and v2 fully client side you'll find the people who care. ffmpeg-on-wasm will hit a memory ceiling on longer videos, but most people opening a browser video editor are doing short clips anyway.
Thanks for encouragement. You are right ffmpeg-wasm doesn't really cut it for long videos but I have pivoted to web/audio codecs now, and there I can work based on streams at least for video. So once I harden the tools a bit more memory limits should be large enough to do some good editing.