###Update###

I tried a bit of Notesnook. While it wasnt bad it didnt quite fit the expectation that obsidian created for me for what I want. Maybe it was user error but I honestly can't say what specific aspect bothered me.
For now I decided to stay with what I have experience witg and bought a year of Obsidian-sync for 1 Remote-Vault

Thanks to everyone that suggested me solutions to my really specific problem. I appreciate that and I love(d) the discouse I seemingly sparked in this post.
Please continue commenting. Maybe someone else still hasnt found their solution yet :)

Original Post:

Hello fellow lemmy users, for the lack of a better fitting community I hope my request for help fits here the best.

I am a bit of a scatter-brain, have some notes in Google Keep, OneNote, Obsidian and in GitHub or other places. This is partially multiplied by splitting my work stuff with my home stuff.

What I like about every app I use so far

• OneNote: I like the way I can write on something like a canvas. Very useful if the note does fit the general theme of the page but not at the exact position. Also helps by utilizing the big space of a horizontal monitor. Also it now sports a very good mobile editor.
• Obsidian: So easy to backlink between notes and I love the graph view. I also like the extension "code styler" which lets me format inline code blocks with syntax highlighting (e.g.: `{powershell icon} Get-ChildItem -Path C:\Path\To\Folder -Filter XYZ*`).
  I like to learn scripting but I also use obsidian for RL-stuff and technical non-code like keeping track of configs, settings, wishlists etc.
• Google Keep: I bastardize the check-box feature to keep track of (online) shop orders. Mostly the only reason is that checked items get hidden in a collapsed section
  
  Any other program that let's me to that (even with plugin/extension) is a valid replacement candidate

What I dislike:

• OneNote:
  • Quite difficult to link between notes (unsupported on mobile)
  • Limited to 1 folder deep notes. Currently work around that by using the horizontal space or multi notes.
  • A bit clunky to edit bigger notes
  • By microsoft.
• Obsidian:
  • No native way to have everything on a server outside of using the obsidian-sync service for $4 or the community plugin which requires me to use some novel type of db called couch-db (ugh, another service to keep updated/troubleshoot). I can stomach the $4 but am limited to only one vault which I don't really like.
• Google Keep:
  • Google
  • No real way to have everything backed up. Only use it for quick notes or for my shipment list. Everything else is probably exported to Obsidian/OneNote if I feel like doing house-keeping.

How I currently manage/store my files:

• Right now I use
• OneNote which is stored on OneDrive (I like how Outlook (classic) works and I got 1TB of cloud storage),
• Obsidian which syncs with the plugin "remotely sync" to my OneDrive folder.
• Google Keep: Dunno. Probably some account storage on google

What I want:

• A primarily server-side setup or with a native sync feature that works like on OneNote: The true source is my server or the cloud, the client only streams/caches the data locally. I have no problem with individual markdown files.
  I just dislike the general need to sync them manually with external tools like syncthing.
  I already have a good backup solution on my main server and secondary server (For the curious: Veeam backup and replication that backs my proxmox VMs). No need to manage another set of backups. Another reason I want everything in one spot as I already have everything scattered.
• A tree view of my notes like obsidian and OneNote does. Plus point if the app can even do sections like OneNote does.
• (Optional) A way change-log of the edits done. Some apps do it by implementing git or have a very rudimentary way to manage that
• Mobile/desktop companian app: PWA is okay but I would probably miss out on the caching feature. I would prefer an actual (android) app on my phone. Same for Windows.

What I found so far but have issues so far:

• silverbullet: Server-side but seems to miss the side bar with the tree view (which can probably be added by another extension). Seems like the best candidate so far
• Joplin: Seems alright to use but I can't use callouts which (to me) is mandatory to use with coding/scripting tasks.
• Obsidian: Fits best of all I found but I dislike the $4. But still miles better as the former option which was (i believe) $15 monthly
• BookStack: I bit limited how it manages the change-log. Seems okay
• Outline: No way to sync it without paying beyond manual sync. Didnt try it out much but I like how it looks.
• Logseq: Same issues as with obsidian: Paid sync. Didnt look much beyond
• Joplin: Sufficient but no callouts :(
• Trilium Notes: Maintenance mode. Not a deal-breaker but I don't want to migrate something that could maybe die :/

Thanks for reading the wall of text and I wish you a good start into the year of 2025. ✌️