Logseq is a Personal Knowledge Management application that is developing its own "Whiteboards" feature using Tldraw library.
Logseq Whiteboards is actually in beta and accessible for testers that support Logseq with at least 5$/month, but it will be available in a few weeks for everyone and as Free and Open Source Software (like the rest of Logseq).
Bad3r
commented
1 year ago 
Logseq is a Personal Knowledge Management application that is developing its own "Whiteboards" feature using Tldraw library.
Logseq Whiteboards is actually in beta and accessible for testers that support Logseq with at least 5$/month, but it will be available in a few weeks for everyone and as Free and Open Source Software (like the rest of Logseq).