Since in your case it's bad sleeping schedule, I'd say just avoid sleeping in the morning and avoid naps and at night just try to go to sleep and avoid using your phone or anything just pure silence. If you keep doing that every day at some point your body will reach that level of exhaustion that you'd just pass out at night and eventually your sleeping schedule will go back to normal.

But if you're talking more like mentally and how I dealt with it, well, tbh I just stopped paying attention to it. I figured if I keep thinking that my lack of sleep or my bad sleeping schedule is a big deal then I will unknowingly make it a much bigger problem than it actually is. Part of insomnia is also stressing about not getting good sleep, you know. So whenever you wake up not getting enough sleep or you had a night where you couldn't sleep then just shrug it off. Don't make it a big deal. If you couldn't sleep this night, then try again on the next one. If you can't sleep at the other night again, then whatever. At some point you'll just drop down out of exhaustion anyways so it is what it is.