Hi @danwolch
I cannot tell which queries Metabase are executing, but I doubt it's sync. It's more likely scan or perhaps fingerprinting. I'll need to see the query.
There are a lot of sync/scan issues fixed since 42.2 - and a complete overhaul of field values (scan) in the upcoming v44.
Though, for some databases, some queries can still be heavy:
https://github.com/metabase/metabase/issues/19470 - upvote by clicking 
on the first post