AFAIK wlroots does support fractional scaling since Feb 23 https://www.phoronix.com/news/Sway-wl-roots-Fractional-Scale

Unfortunately with iOS you are stuck with Obsidian Sync because Syncthing does not work because of the permission model. Otherwise I prefer Obsidian over Joplin for the above mentioned reasons and nice extension ecosystem. It’s easy to get your files out of Obsidian, no vendor lock-in