I think that openssh or any ssh or ftp app should facilitate this.

Nice, I’ve been doing something similar, using the obsidian-git plug-in for Obsidian and the Working Copy app on iOS.

Obsidian is my front-end, and it saves the notes in markdown files in a git-synced folder on my computer.

The plug-in pushes and pulls automatically, and Working Copy does the same thing on iOS, just before opening the Obsidian app on iOS.