New to this possibility, tbh, but I'd assume you'd need to be a DM admin for the destination cluster and have sufficient rights on the cloud side to fetch the related connector.

Have you already tried with having all the checkbox enabled under "Protocol & Templates"?

That is currently allowing a user to download the protocols via the
"update center" link at the top right corner:

To add a protocol via the old DCP, these had to be enabled:

HTH