@NineLizards, I see your question has been answered perfectly fine by @RetiredWingMan 😉
in short:
download offline maps enable sync (preferably all, then you will never have to look at it) let it complete a sync once, it will resync every time you start the app or enter the routes menu automatically and download changes only (if there are any) enable offline navigation in the app menuNo need for confusion ever again (concerning offline routes that is... 😉 )