I manage to enable custom repo on my AK with by removing the subscription part of my playbook then switch the content_overrides part to enabling wanted repos instead of disabling unwanted one.
Now when i register new host, custom repos are well enabled by AK
So the whole point of SCA is that you no longer need to provide subscriptions on activation keys.
However, if you change the activation key, you’ll need to force re-register all systems that use it 
That’s what I do in my Ansible playbooks (or, depending on the host, I just reinstall the whole OS, sometimes that’s less work 
)
Activation keys have always only affected hosts at registration time. I don’t see how subscriptions make a difference there?
They shouldn’t as far as I know, if you’re using SCA. I also forgot to mention you can also ‘just’ enable the repo with subscription-manager repos --enable=<your repo label here>