The last I checked, NextDNS uses Google Cloud (for streaming logs), Vercel (AWS) (to host the website), and Cloudflare (as a CDN). Each of those providers, from what I can tell without access to internal systems is, have access to unencrypted customer data. So, make what you will.
True, but don’t think privacy enthusiasts prefer other DNSes over their VPN provider’s or ones they can self-host, like Pi-Hole / Technitium.