I am using the same process with GCP with several projects, and never had this issue.
Not able to enable APIs (Cloud Run etc..)
Missing Required Permission
You are missing the required permission: billing.accounts.list
I am logged in as an Owner
The project has a Billing account linked
The Cloud Console Engineering team is aware of this issue as it has been reported a few days ago. A workaround by the engineering team was to enable them with the gcloud command tool.
A fix for the issue has been rolled out which should take effect at some point today to enable your API's but sometimes it takes some time to see the changes.
But probably you will be able to enable your API tomorrow.