More:
Editorial
macOS Big Sur telling Apple what app you’ve opened isn’t a security or privacy issue
Not using Sur, but I did notice a change of character set data, in an older Mac OS, overnight -— as a result of the older Mac OS communicating with an Apple server.
24/7, a Mac (if allowed by the user) is in routine contact with Apple via at least:
AppleIDAuthAgent
configd
helpd (AmazonAWS sub-contracting to Apple)
ntpd
ocspd
sntp
syspolicyd
trustd