Unfortunately, there is nothing you can do on the user's side to overcome this. The problem with Android is that due to Google's restrictions, file system access is extremely slow in comparison to desktop operating systems, hence synchronisation also takes much longer 
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I believe he only workaround that actually works is to use a separate profile with essential notes, and only sync that with Android. The more notes (both in number and complexity) you've got, the slower synchronisation becomes.