EDIT : Found it.

I've seen this being said mostly on reddit but haven't seen any source/reference to this claim. Is this like an NDA that devs sign ? Has anyone reported on this/archived it ?

If you want cross platform, Joplin might be best option right now. But I am keeping an eye on Beaver Notes.

As others mentioned, Joplin is a solid option (with lots of plugins too). Notesnook too is good (if you're willing to pay a subscription). If you are willing to wait a bit, there's Beaver Notes. Currently they are working on syncing between devices and a new mobile client.

Look at the license file. They are using their own custom license. Being made available on github doesn't make it is open source. Anytype could be considered 'source available'.

(I specified this just because OP asked for open source. I contribute sometimes to foss apps, and it bothers me that the term foss get misinterpreted. It's not you, even most companies don't know the right terms to be considered foss. If you look up anytype on wayback machine, they used to proudly claim they were foss lol)

Anytype isn't 'open source'.

I forgot to share the url. It's this one.

Warning : you can't opt out of cookies for reason

I typed "found it" after just seeing the post/headline on lemmy, but reading through the article, the allegations are from Ubisoft and fucking WB for 2 of their micro transaction heavy games. I don't think this is what many people were lead to believe with the comments here. I initially thought the allegations were from poor indie devs. I don't fucking care what Ubisoft and WB does, they are not saints either.