How to keep my son in his room at night?

I’m writing this at 1:15 after hearing my son’s door open and running to his room. Luckily I was still awake. He very rarely leaves his room without making a single sound, but the monitor picked nothing up.

I’ll preface this by saying I know the usual options but genuinely none of them seem like they are viable for us - see below.

Door handle covers - we have the long lever handles, not round knobs and the options I see on Amazon seem to be for things like front doors? They make the plastic ‘stoppers’ to prevent the handle from being levered down, but you couldn’t then open the door from the hallway, and he would need to set the stopper up himself when going to bed? Unless I’m misunderstanding.

Gate - we live in a new construction and our door lining is stupidly shallow. We couldn’t position a gate and still have the ability to close the door, which we need as it’s an apartment and he’d hear us in the evenings.

Lock - is it too much to add some sort of slide bolt to the outside? I have no interest in a key/magnet lock as in a true emergency it only takes a second to lose the only access to your child’s room. Adding some sort of additional lock seems to trigger ‘evil parent locks me in my room’ mentally for me? Am I being stupid?

The only thing I can think of is 2 gates in our hallway, so that if he leaves he can literally only move between his bedroom and ours. We could then extend it further in the future to include the family bathroom. Ideally I wouldn’t want a maze of gates to navigate 24/7 but it seems like my only choice.

Thankfully we have no stairs to contend with but obviously fire safety/general roaming around the house unattended is still a concern.

Anything I’m missing?