There are plenty of IPv4 addresses for server use, and IPv4 in client networks is easily accomplished using whatever form of NAT you prefer. DNS64+NAT64 will wo

There are plenty of IPv4 addresses for server use, and IPv4 in client networks is easily accomplished using whatever form of NAT you prefer. DNS64+NAT64 will work fine for IoT crap (not like your thermostat is validating DNSSEC), and a whole bunch of ISPs rely on DS-Lite+CGNAT to allow IPv4 connectivity over their essentially IPv6-only backbone already. Publicly reachable IPv4 on the consumer side is dying rapidly, but IPv4 LANs and servers can still work exactly because of the versatility IPv6 allows.