We have a similar use case
i have a couple of wifi smart plugs - i've flashed them to tasmota so no talking to the cloud, they only talk to homeassistant on a raspberrypi. 1 turns on some leds outside on the deck when the sun goes down and off at 11pm. the other connects to a separate router for the kids ipads that sits in the roof above their bedrooms. The plug turns on the power at 8am and off at 6pm. I could setup something similar on the main router if i paid to upgrade it. This solution cost me AU$9 and about 30 minutes of my time.