What am I missing with Obsidian Sync?

I’ve been using Obsidian for a couple of months now and loving it. I have been syncing my PC & Android phone using Google Drive. Not perfect - due to having to use Folder Sync to overcome not being able to access Google Drive directly - but it worked.
After seeing a YouTube video on Obsidian Sync and seeing how quick data appeared after a note has been updated, I signed up for a month. It works very well - while both screens are open. However, I rarely have both screens open.

I mainly work in Obsidian on my two PCs - home & office. With Google Drive the data was already synced and all I had to wait for was Obsidian to index - which took just a few seconds. On Android, assuming Folder Sync didn’t have any errors, it was the same - a few seconds.

With Obsidian Sync, if I have made a lot of changes say, move a folder or rename a tag or two, I have to wait considerably longer for it to sync and then index before I can use it. This is especially noticeable if I open Obsidian on my Android. I have tried keeping Obsidian open in the background but it still doesn’t sync until I go to use it. Surely this can’t be right or am I missing something?