Bug reports and questions: open an issue on GitHub. For license or billing questions, reply to your Lemon Squeezy receipt email.
Pastyx needs Accessibility permission to press ⌘V for you. Open the menu-bar icon → Enable Accessibility… and follow the steps. On the Mac App Store version, drag Pastyx into System Settings → Privacy & Security → Accessibility.
Open Pastyx (⌘⇧V by default), press ⌘, and click the shortcut to record a new one.
No. Items that password managers mark as concealed are skipped, and Keychain Access, Passwords, 1Password and Bitwarden are ignored by default. Right-click any clip to ignore the app it came from.
One license activates up to 3 Macs. To free a slot, open Settings → License → Deactivate this Mac on the old one.