If it's open source, extremely reliable, cross platform including Android, opens in less than 2 seconds(like Google Keep does), and is packaged for Linux in a m

If it's open source, extremely reliable, cross platform including Android, opens in less than 2 seconds(like Google Keep does), and is packaged for Linux in a maintenance free way(AppImage/Flatpak/single binary), then probably. Sync has to never lose data due to conflicts, the desktop version needs to not be entirely keyboard shortcut driven and not take a week to learn. I've tried pretty much all the notes apps, none are 100% perfect, but Google Keep is hard to compete with. I suspect it would not be too hard to make a great one, because you could use SyncThing and plain text as the backend, and I've thought about doing one myself, but the effort of maintaining a cross platform app by myself is more stress than I want to add.