Answering my own question…
I temporarily moved the domain’s name servers to Dreamhost (which happens to be the domain’s registrar). Then I deleted the domain from DO account A, which enabled me to create the domain under DO account B and add the relevant records.
Then I swung the domain’s name servers back to DO.

I dont think you can do that..

DNS record needs to be manually updated at your domain’s end and in DO panel as well since, as far as I know, when you transfer a snapshot, it only carries data but leaves out the IP address.

So you need to redirect those settings and update the DNS records as per the new IP address..

That’s not what I meant.
I have manually updated all of the records as needed - but I had to do it from the account (account A) which no longer has any droplets hosting the domain.
In the future, when DNS updates are needed for the domain, I want to be able to make those changes from account B - which now has a droplet hosting the domain.

I did wait a few hours for the world to discover that the NS had changed from DO to Dreamhost.
But then, I deleted the domain from DO account A, and I was immediately able to create it on account B.
So I think the transition was transparent to the end users.