A user cannot register any public deploy keys on .com (SaaS)

https://docs.gitlab.com/ee/user/project/deploy_keys/index.html#create-a-public-deploy-key

Create a public deploy key
Prerequisites:

You must have administrator access.
Generate an SSH key pair. Put the private SSH key on the host that requires access to the repository.
To create a public deploy key:

On the top bar, select Menu > Admin.
On the left sidebar, select Deploy Keys.
Select New deploy key.
Complete the fields.
Use a meaningful description for Name. For example, include the name of the external host or application that will use the public deploy key.
You can modify only a public deploy key’s name.

TODO

• Make sure if Create a public deploy key is available only in self-managed !90563 (merged)

Refs.

cf. https://forum.gitlab.com/t/need-to-add-public-group-deploy-key-no-admin-section/71164