Sync has always been a painfully slow Firefox user on Android mobile, We usually had to wait from anywhere to 5 minutes to multiple hours to be able to access the tabs of another device.
On desktop we could speed this up by decreasing the values of services.sync.scheduler.activeInterval and services.sync.scheduler.immediateInterval (the integers stand for seconds). This enhanced the overall sync experience, but it’s still far from what would be considered desirable. On Android we still need to do a manual sync from time to time.
Request to Change this Setting on Android where user get bookmarks, Password etc. etc in within 1 to 5 Seconds ( similar Service offer by Apple Like Immediate Sync)