I don't have much to say regarding your work issue with IPv6 and a K8S cluster. However, I do have some comments regarding DNSSEC:
As I understand it, there you have basically 3 options for local DNS w/ DNSSEC - 1) you can run a local recursive resolver, such as BIND; 2) You can use a non-validating stub resolver which requires that you trust the the recursive resolver you use _and_ the channel to the resolver; or 3) You can use a validating stub resolver. The problem with option 3, is that I don't believe it's possible to do DNSSEC validation for a record without fetching a bunch of parent records - so you end up running something that looks a lot like a recursive resolver with a cache, so, its really not clear to me why someone would do this over option 1.
Anyway, that basically leaves you with two options: a recursive DNS server or you have to trust the recursive server that you do use and the channel to the server. While its fine to run your own recursive server if you want to, there are legit reasons someone (such as myself) wouldn't want to - its another service to manage and it may not perform as well as a shared cache in a recursive server someone else is maintaining. What that leaves me with, is that I want to use a non-validating stub resolver and I suspect that is true for most people as well.
Unfortunately, as DNS traffic is not encrypted, when I use a non-validating stub resolver, it's easy for anyone that can eaves drop on my traffic can log where I'm going. Anyone that can modify traffic, can send me whatever responses they want. It doesn't matter if the domain I request is protected by DNSSEC if someone in the middle sends me back a bogus response that my resolver has no way to verify.
DoH actually works alongside DNSSEC in some situations - by encrypting the channel between my stub resolver and a validating recursive resolver, it means that DNSSEC validation can't be easily stripped out by someone that controls whatever local network I'm connected to.
Even with a local validating recursive resolver, you have little protection against NXDOMAIN substitutions and the like unless the domain you are talking to has DNSSEC enabled. However, DNSSEC is being slowly deployed and, in my opinion, it's very unclear if it will ever get to 100%. Unless it does, something like DoH still has value in protecting users from interference on the local network for non-DNSSEC domains.
My points: I don't think that a Local DNSSEC resolver running on everyone's computer is realistic; DoH actually benefits DNSSEC by securing the channel between a stub resolver and a validating recursive resolver.
Sources:
https://tools.ietf.org/html/rfc4033#page-12
https://lwn.net/Articles/665055/