Re: Upgraded OS to 14.2.1 ...... the system is very slow
.... some apps including Pages and Numbers keep freezing requiring a 'force quit' as app not responding.
Sometimes a Mac needs time to finish the re-indexing that Spotlight may do after the update.
Wondering if you are short on storage/ memory space on your Mac:
Eg: A Mac needs around 50Gb free in which to operate smoothly.
See used and available storage space on your Mac - Apple Support
or
Some non-Apple (third-party) apps installed may now need updating for compatibility
or
Unnecessary third-party apps like ad-blockers, virus-checkers, cleaners and the like, even VPN and non-Apple browsers do often cause issues ... use the uninstallers from their developers, or just try turning off any such apps ... see if it makes a difference.
Also: Apple Support have an article online that may be helpful: If your Mac runs slowly - Apple Support