As pointed out above, Proton used to have VC investors. Brave has very sketchy ownership Brave - Crunchbase Company Profile & Funding and tons more investors. I don’t think this warrants removal though.
Cloaked has raised much more money too Cloaked - Crunchbase Company Profile & Funding (3x more than Skiff which makes no sense because they released a few months ago ?).
Notesnook is popular despite being in Pakistan (way worse than US/EU/UK/AU privacy laws).
This list may just have to change over time. Services will come and go, unfortunately, but it’s the way the world works.