Quest Chronicle keeps track of the games you own across every console, what you are playing now, and what you have finished. It runs on the Mac, the iPhone and the iPad, and syncs through your own iCloud.
Yes, for Steam and Xbox. Settings, then Log What I'm Playing. Steam needs a free key from steamcommunity.com/dev/apikey plus your profile name; Xbox needs a free key from xbl.io. The app checks every few minutes while it is open, and when you open it again it catches up on anything you played while it was closed.
SteamGridDB, with a free key of your own, and IGDB if you set that up as well. Both are entered in Settings under Cover Art. Artwork is stored on your device and shared to your other devices through iCloud.
Sync runs through your iCloud account, so both devices must be signed in to the same one. Games travel in seconds to a few minutes; cover images travel separately and can lag. If a device looks wrong, Settings, then iCloud, has a re-download that discards only that device's local copy.
Yes. Settings, then Export Game Library to CSV, writes the whole library to a file you can open in any spreadsheet.
On a Mac, press Command and / , or choose Help then Keyboard Shortcuts, for the full list.
Ask in the Quest Chronicle Discord, where there is a bug-reports channel, or email eric.linder@gmail.com. If you are reporting a bug, say which device and which version (Settings shows it at the bottom).