So in short, what issue you're experiencing right now?

if it's about Android syncing, please note that Joplin does not have a background sync on mobile devices. When Joplin is closed, sent to the background or the device is put into sleep (display off), the sync is interrupted. So please disable the lock and leave it for several hours with the app in the foreground.

It is highly advisable not to interrupt first lengthy synchronization. It may take time, sometimes dozens of hours.

So, it's best to disable the time out of screen lock and leave the phone syncing overnight
Secondary synchronization cycles will be much quicker (about several seconds)