When I was younger and physically able, I worked many years evenings/late-nights doing cleaning - office buildings, at a clinic, banks, places like that. Some accounts during those years I was the only one there, literally...which was great because I had no boss breathing down my neck, no customers to deal with. Plus it was like a nightly workout depending on what my specific job was for an account (for instance, one building had about 6-8 offices in it that I would dust, vacuum, wipe down their breakrooms, empty garbage cans, sometimes clean bathrooms which was the gross part but compared to dealing with people, I'll take cleaning a bathroom...basically I did all the work there since it was only me. But at the clinic I cleaned at, I *only* dusted or vacuumed or whatever - someone else emptied garbage, someone else mopped all the floors. So what specific task you did depended upon which account you worked at.). I might also have to sweep and/or mop the common areas - halls, stairwells. I know a lot people would NOT like a janitorial job, or think it beneath them, and sometimes if employees happened to still be there when I showed up they'd act like I was sooooo inferior to them or else they'd just totally ignore me, which was fine with me). I liked cleaning though because of the solitary nature of the work and I got some exercise too, and you got immediate gratification seeing something messy or dirty get clean, so it was kinda therapeutic for me that way. Pay wasn't going to let a person live a luxurious lifestyle, but then again it all depends on the company you work for, how many hours a week you work. I made enough to live OK.
I also for awhile worked overnights at an answering service which was AWESOME because NO ONE was there all night long but me, just answering phones and sometimes paging (back when people used pagers!) people if necessary. Not much interactions with people though, and it was only via the phone - and sometimes, since it was overnight, the phone wouldn't ring at all hours at a time so I'd just sit there and read. I know answering services probably are obsolete now but maybe there are similar type jobs nowadays?
I still think nighttime cleaning jobs would be the best. I used to listen to music or talk radio while I worked, it helped the night go even quicker.
Good luck, I hope you'll find something that will work out for you. I understand your situation which is why I too always tried to find jobs that required no, or VERY limited, interactions with others.