@adar I've been trialling spacedeck for a project, but we ran into various technical issues. Getting sluggish. Not sure if it's due to the hosting or the software though.
https://excalidraw.com/ is very nice though, and open source, however self hosting doesn't support collaboration features, as it's tied into some Google databases... Apparently they are working on that, but didn't see a reply to my question about the status of it yet.
Main instance is usable though.
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