I was able to mitigate this issue on my ipad. I am using a self-created CA cert via openssl. Prior to updating to ipadOS 18.2, I was able to import the CA as a profile, but was unable to see it in the cert trust settings. Unfortunately, I didn't track what version I was on prior to 18.2. After updating to 18.2 and removing/re-importing the profile, I could see and enable the CA cert in cert trust settings. The same cert works without issue on my iPhone and vision pro.