esp-rgb-led-matrix VS templates

Since you're (seemingly) already familiar with Arduino, just use that as your framework. You can program the ESP32 in Arduino and access any library you're familiar with as well as handle Wifi.

You can buy an RGB matrix on Adafruit and they sell esp32 boards that can drive them directly,so it's essentially plug and play, no hardware knowledge necessary.

If you prefer to DIY but still need some guide, check out this project that documents both hardware and software to achieve what you want to do:

https://github.com/BlueAndi/esp-rgb-led-matrix

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.