A DNS error has nothing to do with WP the site, as the name indicates.
This is more like a telephone directory entry being temporarily unavailable for some reason, but the person the entry references is nevertheless still reachable and while DNS is a global service, everyone still connects to a specific DNS provider as the starting point of that service. If that fails, the telephone directory entry is unavailable on that provider.
If it's possible, I suggest you change your primary and secondary DNS addresses to Google's public DNS servers, at 8.8.8.8 and 8.8.4.4
Slow page loads - I see this in maybe 1 out of 30 pages: it can be a delay before a page is displayed, or a delay before the "This message has been posted successfully" message appears.
No website "likes" one type of connection over another - but local/nearby network conditions/performance may give that appearance.
There are several connections involved between a PC/mobile device and WP, all of which contribute to your connected experience.
Most notably, WP is accessed through the CloudFlare service and while not perfect, it insulates users from many potential outages.
But even CloudFlare is dependent on the performance of the network, the string of connections, between your device and the relevant CloudFlare node and neither it, nor WP, can help with that.
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Giraffe: a ruminant with a view.