Your clients are only invited once to the portal.  Once they accept the invitation, even it it was in a prior tax year, they will show up as "invite accepted."  You do not need to send another invitation to an existing client who was already set up with an account in your Intuit Link portal.

For client activity updates, are you sure you are looking in the right year tab -- TY 2022?  You won't see any activity updates for another tax year if you are in a different tab.