Living in a new world – Security Cameras everywhere

Can cameras be used for Hashgachos / Cholov Yisrael?
Do we still need on site Mashgiachim?
Security cameras around homes and shuls; does it create a problem entering / walking by on Shabbos?
Can you use a camera to monitor an elderly parent who’s in quarantine / in the hospital on Shabbos?
Can you use a nanny cam or baby monitor on Shabbos?