> It's all bout money encapsulated by "security" marketing buzzword. Yes, DoH is an improvement over old plaintext UDP DNS. But why should I used a nobody service over Cloudflare or Google that update their databases within seconds all over the world and rarely if ever faced a downtime?

It is not so straightforward as always being an improvement. For example, a user can be uniquely identified through session resumption session ID whereas with plaintext UDP behind a firewall with many others doing lookups unique identification of a user can be close to impossible.