Looks like it does not allow new channels for 6 GHz Wi-Fi. 802.11be (Wi-Fi 7) already covers full range of FCC's allowed frequency range. IEEE committee may add new channels in 802.11bn (expected to be ratified around 2028, and commercial name will be Wi-Fi 8) but it also looks like a low probably, considering both 802.11ax (Wi-Fi 6/ Wi-Fi 6e) and 802.11be (Wi-Fi 7) mostly focuses on reducing the interference between different networks by reducing the collision, instead of widening the spectrum (BSS coloring, Flexible Channel Utilization etc.)
afaik, pretty much any user-agent changer works. At least that's what one of my colleagues uses to join MS Teams meetings on Firefox. Simply switch your user-agent to Chrome, and it should do the trick.
Honestly, it depends on the game. Hence I suggest checking ProtonDB[0] for the games you are planning to play. Most of the reports also have details about CPU, GPU, GPU driver etc.
Anecdotally, I remember playing Team Fortress 2's native port on Intel i7-2630qm CPU on my laptop back in 2012-2013 at 1366*768 resolution with no major performance difference. (setting up bumblebee was not an easy task for me back then.)
