templates VS TasmoAdmin

Setting two on/off cycles with 50 discrete schedules seems like a very inefficient way of doing this when the same thing could be accomplished with two rules. Any compatible device flashed with Tasmota or similar FOSS firmware would make this possible.

Have a look at https://templates.blakadder.com

Another WiFi based option is any compatible smart relay or switch flashed with Tasmota. In Tasmota, SwitchMode 15 decouples the switch state from the relay and sends status changes via MQTT to HA.

2) If you want to switch on/off the light switch in your room, your best bet is to replace your regular light switch with a WiFi light switch. (Yes, you must have some electrical knowledge to do this. But trust me, this is best, most reliable way.) See https://templates.blakadder.com/ for some good devices. Many of them can be re-flashed, so instead of using "their app", the light switch can be a web server that you can talk to from any computer on your network (including your laptop, your phone, etc).

If you're familiar programming ESP boards take a look at this repository of compatible devices.

Wifi switch, I suggest one that runs tasmota. Blakadder website seems to help.

I cannot find the correct model for this plug. On the back it says "WiFi Smart Plug / TWSP017" but I cannot find any reference to this online. I looked at the (long) list of pictures of plugs and sockets at the templates.blakadder.com site, but without finding anything that looks quite like it. There is one power socket, one LED (that never seems to be lit) and one button on the left side. It is a square shape with rounded corners; too generic a description to be useful I'm afraid.

You mention incompatibilities. I am not 100% what you mean but here's a link of Zigbee2Mqtt supported devices and Heres a list of tasmota supported devices . i'd reference these before buying anything.

from https://github.com/TasmoAdmin/TasmoAdmin/issues/114

TasmoAdmin is the way to go. It's for managing a large number of Tasmota devices. It can bulk update the Tasmota firmware, and also broadcast bulk commands via web requests. e.g.:

https://github.com/reloxx13/TasmoAdmin or https://github.com/hassio-addons/addon-tasmoadmin

I recommend TasmoAdmin. You would have to add each device, but after that you can broadcast commands to selected or all devices, and you can bulk update the firmware too. I use it daily to see if any devices are offline, and to switch on/off a device quickly.