Coordination of Benefits Aetna and Kaiser

Hi all, looking for some advice regarding filling out a Coordination of Benefits with Kaiser and Aetna and if it’s necessary in my situation. I have Kaiser through my parents until I am 26 and it is great Insurance. No deductible and all my co pays are $15 (surgery, ER, everything). The only thing is Kaiser does not cover Zepbound (an injectable for obesity) at all and I have been taking it since March. I have been paying $550 with a coupon but it was really expensive so I decided to enroll in Aetna with my new job during enrollment since I heard they cover it. I now have Aetna under my employer and Kaiser through my parents and I have used Aetna now to go see a PCP once (to give me the prior authorization) and get my Zepbound covered. I now pay only $25 a month for it which has been such a relief but now I’m worried about the repercussions of being dual insured. I know I should let them both know, but my Aetna plan does not have good co pays and a large deductible so I would only ever go to Kaiser if I needed any other type of care. Since I am only using Aetna for Zepbound and nothing else, would it be okay to not say anything? I don’t want to jeopardize the Kaiser insurance I already have since it’s really good.

Thank you in advance!