Carnet is one I like, though it's quite early in its development cycle (started less than one year ago, I think). Author is supported trough donations. It also syncs with nextcloud (and is available as a webapp --nextcloud or standalone), and explicitly takes google Keep as an inspiration. The desktop version has a barebones google keep import feature.

https://apps.nextcloud.com/apps/carnet

https://github.com/PhieF/CarnetDocumentation

https://carnet.live

I've been on the lookout for such an app as well, and after trying a lot of different ones, this is my favorite so far.