This is both a problem report, and a feature request(s) combined, hence the blank issue.

The Problem
My Calibre library now has a few thousand books in it (it's been going for 12 years now...), and my Aura H2O simply times out when attempting to sync with calibre-web. The Kobo eventually gave a 'sync failed' message, and my wireshark capture shows that it gave up at around ~286K characters.

There needs to be some method of making large libraries more usable for kobo sync. A few ideas off the top of my head:

• I notice the initial sync sends the full metadata for each book. Is this required? Or is the Kobo smart enough to request additional metadata later?
• How about "archiving" the library by default, and "unarchiving" the books we want to sync? I actually don't want thousands of books on my Kobo at a time...
• Is it possible to recreate the store API, such that one could browse one's Calibre library as though we were browsing the Kobo store, then "purchase" books we want to sync?

@shavitmichael do you have any ideas or thoughts on this?