What you will have to do will vary based on surgery center, insurance, and starting BMI, as well as any co-morbidities.
I started in January with a BMI of almost 50 and no co-morbidities, so I have been trying to lose weight, although now that I have had to wait so long (insurance required 4 months of monthly nutrition classes, and now there are delays due to staffing issues and backlogs due to COVID), I've lost 42 Lbs and my BMI is getting to the point where I'll have to stop losing weight.
However, I don't have to have EGD or EKG or sleep study.
I did have to meet with the psychologist and nutritionist a few times and have their sign-off.