@apollothethird -- The problem is *not* how you detect the browser or screen size. It's about what you do after you detected it. The old model was to load one version of the site for desktop, and another (different) version for mobile. That meant you had to maintain / debug / add new features to TWO versions of the site (really more if you count tablets, wide-screens etc). That model is not sustainable from a development perspective, especially for a small team of volunteers.
With responsive design, the page elements being loaded are all the same for all devices/browsers. The code is the same. Which is much better from a development + code maintenance perspective, mainly because there is only *ONE* instance of code to maintain. All that's different is the *stylesheet* being loaded (i.e. the way the elements already loaded fit on screen).
As to the rest of your message -- I get it + I wasn't criticizing you for speaking up. Sorry if it came out that way. I do encourage constructive feedback, as so are the developers. Btw, I see that they are already hard at work on ironing out things, and I find the interface already improved compared to just a couple days ago. :)
And thanks for donating. I did that too, despite being a lifetime patron already. They clearly deserve it + would like to put another word out there for anyone who can afford, even a little, to continue supporting Lichess. It's really a gift to the world, and should be appreciated at its true value!
Agreed with the forum navigation issue. I opened a topic myself too, merely hours after the launch of v2. I'm sure it will get addressed shortly.
Best regards.