One problem I've unfortunately run into with alternative DNS providers is that Akamai apparently also uses DNS to steer you to the right part of their CDN, and

One problem I've unfortunately run into with alternative DNS providers is that Akamai apparently also uses DNS to steer you to the right part of their CDN, and that the "default" set of servers returned by alternativ DNS providers apparently has abysmal peering with my ISP (not just slightly slower, but positively unusable during peak hours in the evening). In theory EDNS Client Subnet (ECS) is supposed to work around this problem, but a) according to https://www.cdnplanet.com/blog/which-cdns-support-edns-client-subnet/ https://www.cdnplanet.com/blog/which-cdns-support-edns-clien... Akamai only supports this with Google and OpenDNS and b) alternative DNS providers might not support ECS anyway, whether explicitly for privacy reasons or otherwise… Which means I'd basically have to set up a custom DNS resolver in order to special-case queries for anything hosted on Akamai's CDN…