HSTS only says connections must be encrypted, not with which cert... you're thinking of a CAA record. Although a CAA record doesn't mean much if your adversary controls the DNS server.
I think you're thinking of HTTP Public Key Pinning. A CAA record just tells a CA whether it is permitted to issue certificates for a domain.
If you are going to spy on me, please disclose when and where. AFAIK w/HSTS sites they generally don't interdict the traffic (not because they don't want to but probably because they can't).