I see, so my idea was to ship the local database file to platforms, to reduce first start and then update it because I am building a dictionary app and all the entries must be up to date regardless of who made the changes and who’s viewing them. Is that still going to be a significant problem as to speed?
Also, when exactly should I use
await _realm.Subscriptions.WaitForSynchronizationAsync();
As I think I should use it right after start, after acquiring Realm instance and setting up Subscriptions - to download external changes and after I make changes to sync, am I correct?
The last one - should I use any other methods like those in SyncSession - WaitForDownload or WaitForUpload etc?
My original problem is described here btw, please take a look if you get the chance. This is a blocker for me and I am not even trying to make this work now, just want to understand though, for future tries 
Thank you