Scared to let cat roam while not home

Hi all,

As stated in the title, I am concerned to let my cat roam around my apartment while I'm not home. This is exacerbated by a recent event in which a friend had their cat dash while the door was open and was gone for over 5 hours.

I live in a 1br/1b studio and the front door goes straight outside. I adopted about a month ago and have been keeping him in the bathroom while I'm away. I don't want to have to do this forever because I would like him to be able to have the full, albeit limited, space of the apartment when I'm gone for a couple hours at a time.

I've seen the motion detector spray canister and I thought that might work, but there were mixed reviews. I also was considering getting an air tag collar. Does anyone have experience with this situation and is willing to provide some guidance? Thanks in advance.