The 512-bit RSA keys are a distraction. You're allowed to not care about the security of your own domain, but if your DNS hosting provider does not, and you do, get a better DNS hosting provider, all but two (of any size) use stronger keys.

ECDSA P-256 and P-384 are widely deployed. New algorithms will take some time to be widely supported by peer resolvers, just as TLS 1.3 will take time to be widely supported by web sites (browsers are more agile, but many websites still don't do forward-secrecy with TLS 1.2).

Algorithm agility is a thorny problem.