My son uses HA for his Aqara door locks, Ikea temp sensors and Zigbee smart plugs.
One Zigbee smart plug is used in an automation to control a 240V contactor which turns on/off a garage heater based on info from the Ikea temp sensors. He also uses a cheap android tablet for a really nice dashboard.
I use HA with an Insteon modem at our AZ condo. I run Tailscale the HA for remote access.
Finally I use a Polisy/HA combo at our main house.
HA has come a long way and solves lots of smart device integration problems.