I agree with you, but the only alternative is Chrome. If it comes down to Chrome or nothing, I'm probably just going to quit using the internet and go live in the forest.
There's plenty of other options to use instead of Chrome or FF.
Though I am very drawn to ad model it.
Check out brave://sync-internals/, where you have the option to explicitly request a sync operation. You can see details there about how many items have transferred between devices too.
So new bookmarks and passwords I have created haven't synced.
Just checked the page you suggested and passwords are marked as
Datatype preconditions not met.
Not sure what that means.