My experience with syncthing was pretty awful actually. If i deleted something, it deleted from every device, if i added something on desktop, it automatically took storage on my phone. Which were both the opposite of what i wanted. I wanted to leverage storage on my desktop to offload it from my phone, but still have it accessible.

Maybe there were some settings i could change with syncthing, but I lost some files almost immediately because of the destructive sync function without realizing.

It's certainly the closest thing to what I'd love to have however. But there are some major things that are hugely under-appreciated possibilities that it doesn't seem interested in building for.