There’s a pretty active ecosystem of ESP32 projects for HVAC systems. I’ve been working on a few that add Apple Home and Matter support with a local web interface for basic and advanced features. The web interface exposes things Apple Home or Matter protocols don’t represent well. Vane positions, different modes (dry, fan only), equipment diagnostics, remote sensor control, and even peer to peer communication for fully offline control (no WiFi needed). Plus it gets me a control path independent of the home automation stack. There’s a lot you can put on the device itself these days.

With another project, based on the ESP32-S3, I was able to cram grafana style scrubbable charts, full activity log, refrigerant circuit diagram, equipment topology, etc. I'm pretty excited for the ESP32-S31 since it's a nice jump up in performance.