I am using @obsidianmd local so no synchronization. But if I would decide to enable synchronization hosted by the wonderful people of #obsidianMD, the price is keeping me away. 8$ is not appropriate. Way to much.
I love Obsidian and the people behind, but not their pricing policy.
Then syncthing is probably what you want. It’s not a cloud solution, it directly syncs content between devices you connect. And it’s free.
Good luck, no matter the solution you land on!