I have an old netlify account I can no longer access, my email is no longer recognised even though I still receive pipeline update emails to that email address so I can’t login, reset password or anything to get access to the account.
So I created a new Netlify account and added my site again in that account. I now want to use the custom domain currently linked to my old site (bemlw.com) to my new Netlify site (https://gilded-douhua-7e57ac.netlify.app/) but I am unable to because this is currently linked to my old site.
Would you be able to revert your domain nameservers in your registrar? That would help us verify the domain ownership (but it will also cause downtime).
You could also just remove one of the nameservers and that would work without downtime.
Since your DNS zone in Netlify seemed to have many DNS records, I transferred the zone to your new account instead of deleting it. You should be able to use it on your new site now.