Tldr : Need to sync files on my phone and laptop via some remote repository.

So I'm currently using Syncthing to sync my backup files and Joplin notes on my phone and my laptop. I'm not home 3 days a week, so whatever notes I take or changes I make, won't be reflected on my laptop until I come home. I tried next cloud (free tier) sync for Joplin before, but the server has issues from time to time and but the sync part doesn't work properly.

Is there a way for me to use Syncthing or something else using some free or very cheap service and hopefully secure, in such a way that my phone , my laptop and the 3rd service all can be in sync. Also I'm kind of a noob when it comes to all these self hosting stuff, but I can learn some stuff not too complicated though.

Edit : My laptop is not ON during the 3 days I'm out of my house. Ideally once I power it on after a few days it should sync to the latest version.