Perhaps you can have them provide an access key instead? I vaguely recall seeing a button on a 3rd party platform that let me configure my DNS in Cloudflare to

Perhaps you can have them provide an access key instead? I vaguely recall seeing a button on a 3rd party platform that let me configure my DNS in Cloudflare to route to the 3rd party. Not sure how that flow worked to be honest, but I believe there is some programmatic way to delegate.