If you need GLP1 get it . You will not loose muscle if you exercise them with weight training and resistance training which you should do anyways if you are on ADT . According to new guidelines one can get Wegovy if one has any cardiovascular risk regardless of BMI. Since you have diabetes and diabetes increases cardiovascular risk you should be able to get Wegovy completely covered by Medicare. As far as I know, there is Wegovy in a pill form now and it should be much more fordable.

Of course as @jeffmarc wrote - correct nutrition and exercise are the most important parts for any A1C or weight gain problem and should always complement any medical treatment to make it doubly successful. For many it can provide complete solution and for others that need some extra help taking GLP1 meds is OK too. There are some studies that actually show that GLPs help with cancer control and make treatments more effective but much more time is needed to see if those finding truly hold up.