Getting my new cat to eat regularly

I adopted a 3 year old, 13lb male cat about two weeks ago, and while he does eat some food, it’s really inconsistent and he doesn’t seem very food motivated in general.

I’m trying to feed him half wet, half dry on the following schedule: 8am - 1/2 can wet 4pm - 1/2 can wet 8pm - 1/3 cup dry

He’ll eat some of his wet food but won’t ever finish it and sometimes just isn’t interested at all. His dry food he’ll nibble at over time and by the time I wake up in the morning, it’s usually mostly gone. He’s so so on treats, sometimes interested but usually not very.

He is overweight by a few pounds, so clearly at some point he was eating really well lol, but what’s the best way to get him to finish his food? I can’t really leave his wet food out for him to finish it since it’ll go bad and I’m concerned about him not getting enough to eat in general.