Have you written down all the things you need to do? This, for me, gets it out of the swirl of things in my head and when I see it on paper I can start picking out the urgent ones and the easy ones and suddenly it feels more manageable
You're asking them to set up and maintain another platform for you to ... Checks notes... use their FOSS project? Not contribute to development, just...use? That does not seem worth their time. Certainly sounds demanding to step into a project and tell them to do things differently otherwise you won't honour them with your presence
You're not "locked out". You choose to exclude yourself by placing such a high value on privacy. Privacy for what here? For some near-public announcement threads and support channel chats that anyone else in the channel could screenshot or download or post online anyway? That is your choice but framing it as the project developers locking you out is strange.
There's a difference between too many people stopping and no-one stopping though. In OPs situation it sounds like it was right in front of them. That's different
I would argue that it is as close as you can get to WYSIWYG without being it. Logseq works with blocks, which in most cases are only a line or two long. Every block on the page, except the one you're actively clicked on /working on are WYSIWYG.
There's no rendering etc, you just click off the block and you see it
Try logseq, it's a foss alternative to obsidian