If adding new iOS test devices to Apple Developer Portal is a chore, here's Codemagic's tutorial how to simplify this process – the job is done in just several clicks and a couple of taps.
This video will teach you how to store sensitive values. Codemagic has added a Global variables and secrets section to the team settings page so you can manage all your secrets in one place for your codemagic.yaml files. This means you will only have to update that expired certificate in one place, instead of all your apps.