Just remember, if you run your own DNS, and you do so for a mission critical platform, the platform is exposed to a udp DDoS that will be hard to detect let alone prevent.
Unless of course you will invest 5-6 figures worth of US dollars worth of equipment, which by then you can look back and ask yourself, was I better off with Google Cloud DNS, AWS Route 53 and the likes.
Not that I disagree with the fact that these risks exist, but how is that different than running any other service for a mission critical platform?
The main thing I can think of is DNS amplification attacks, but that's more your DNS server being used as part of a DDoS attack rather than being targeted for one. Also (afaik) resolvers are more common targets for DNS amplification than authoritative.