I empathize with your situation regarding your lost pet. When my dog went missing, I used a search service that aided in our reunion, Kindly send a text to pet_finders_ltd on Instagrm, This
Resuce Team actually help me in tracking my Ben back to me in less than a week. I still thank them every day, hoping they'll find yours soon.
Put out something that he's familiar with that carries his scent (a bed, a blanket but NOT a litterbox), call for him in the quiet, still hours (12am-7am) THIS IS SO IMPORTANT, put out food in intervals (not at night) when you can keep an eye out. Lost pet cats go into survival mode super fast, you may need a humane trap if he doesn't turn up right away. Talk to your neighbors (most don't go far and find an open garage or shed to huddle down) and put signs in your local pet store (if someone takes him in they will need litter and food). I hope you find him ❤