Hi @conor,
With Premium you are able to tweak some of the advanced settings. This post goes over some of that: Recommended "premium_conf.txt" settings for gigabit connection (1Gb) to increase speed? - #4 by Tony
Api rate limiting can become a concern as you push these settings up, though, so care needs to be taken or else you can end up making the situation worse.
A blue checkmark basically means that there is nothing actively syncing or that needs to be uploaded. It doesn’t indicate anything about the downloaded items since having some items synced and some items as placeholders is a perfectly valid “synced” state, as far as odrive is concerned.