is NextDNS affected by new DNS vulnerability allows 'nation-state level spying' on companies ?

This is affecting DNSaaS (that's authoritative DNS as a services), we are are cloud DNS Recursive Cache Resolver. See the details of the vuln here: https://i.blackhat.com/USA21/Wednesday-Handouts/us-21-A-New-Class-Of-DNS-Vulnerabilities-Affecting-Many-DNS-As-Service-Platforms.pdf

NextDNS is not hosting customers domains, thus this is not applicable.