Maybe they can use a framework that makes it easy to press a button to switch between light and dark views. I'd prefer it if every website used dark mode.

Cloudflare has been more friendly to privacy and freedom of speech than most large companies. What company, that also provides DDOS protection, would be a better option in your opinion?

For the sake of someone that might be able to take this on, you need to be much more specific about what exactly you want running. You can't just write things like OnePlus. You need too explicitly spec out concrete phone models. I suspect the hardware acquisition costs would exceed the bounty.