Apple Search Ads - Create Certificate button missing

Same problem, also asked apple support weeks ago but they just respond, that the request is forwarded to customer partner team and that they have a lot of requests in the moment. Struggeling since 3 weeks with this issue.

You can use OAuth2 replaces key and certificate credentials authentication in previous versions of the API.  

Please note, at this time, you need to invite a new user to your Apple Search Ads account and provide them one of the API user roles (API Account Manager, API Account Read Only) in order to create and edit an API Public Key in UI. Only these API user roles above are able to create and edit an API Public Key within your Apple Search Ads account.

For more details regarding Apple Search Ads API process, please reference:

Implementing OAuth for the Apple Search Ads API

Note: Apple updated Apple Search Ads API v4

For example:

When you have accessToken try this curl

curl --request GET \
  --url https://api.searchads.apple.com/api/v4/me \
  --header 'Authorization: Bearer {access_token}' \
  --header 'X-AP-Context: orgId={your_orgID}