If you have git and a GitHub account, then you can set it up in a couple of minutes with these 10 simple steps:
Go to your GitHub account and create a new repository for your Obsidian vault
Copy the SSH URL of the repo (e.g: git@github.com:Your_resp/notes.git)
Download Obsidian Git from Community Plugins
After installing and enabling the plugin:
Cmd+P
Execute Git: Initialize a new repo (this will create the .git folder in your vault)
Go to a terminal, cd into your Obsidian vault and add a new origin to your local repo (e.g. git remote add origin git@github.com:Your_resp/notes.git)
Commit all the changes:
Cmd+P
Execute Git: Commit all changes (this will commit all your notes in your local repo)
Go to your terminal again and push the changes to the remote repo git push -u origin main (you need to do this just once to create the branch in the remote repo).
From now on, whenever you want to backup your notes, just:
Cmd+P
Execute: Git: Commit-and-sync
Profit!