There's only one catch: you need to give it a Google Cloud API key, because it uses its OCR and language services. However, what a single person may use, it'd most likely be in the free tier range and would cost $0.00/month. So it's mostly an inconvenience.
It works on Windows and also X11 Linux. Not on Wayland or Mac, for now. Nothing fundamentally impossible there, I just need to test and polish the rough edges.
It's open source, GPL-3.0.
And if you care, it's not Electron, it's Qt. Nowadays we should frugal with RAM :)