Cheap e-ink screen from aliexpress, running esphome pulling data from home assistant every 30 seconds. It got time and date, temperatures, time untill the next buss leaves from the nearest bus stops, range on my car, power usage and price, and the three next items from me and my wifes shared google calendar. I got it framed professionally by a local framing workshop. They were a bit confused and hadn't done anything similar before, but they did a great job. My wife isn't always a big fan of my home automation adventures, but she loves this screen!
Edit: For some reason my picture didn't show up. Link here I think: https://vlemmy.net/pictrs/image/0f583c6d-f9b9-4d7a-91cf-6365b2d88d96.jpeg
I'm by no means an expert, and I'm not sure what API keys you are referring to. I know that Tuya smart devices usually have two versions, a wifi and a Zigbee one. The wifi ones require you to add them using a terrible smartphone app, and the integration with Home assistant sucks. The Zigbee ones work like any other zigbee device, locally controlled. I have several Tuya Zigbee devices which works great, they are integrated in home assistant using zigbee2mqtt.