Offline-first Markdown notes sync between Linux, Android and a self-hosted mini PC

Hi! I bought a mini PC because I want to try homelabbing. I started with AI, but I hit the wall pretty quickly, where I had no clue what was going on or how things worked. I’d like your help with one of my goals. I have a notes/ directory on my laptop containing .md files, which I edit with Neovim. I’d like to use my mini PC to keep everything in sync, so I can edit my notes from my other laptop as well as from my phone using Markor. Basically, I’m looking for a Google Keep–like experience, but where I can choose my own editor on each device. An important requirement is that I want to be able to edit my notes locally even when I don’t have an internet connection. Then, once I’m back online, the changes should automatically sync with the other devices and handle any changes that were made while I was offline. I’d appreciate any tips or suggestions!