It depends on the GPU I suspect. The 6XXX series doesn't appear to have that issue, at least not in a significant way. But yeah, the 7XXX series having power consumption issues isn't too surprising.

As for the quote, the "more aggressive ramping" is about its behaviour under load, which you probably do want if you're playing games.

You can revert the change in the same way as you can make the change now, with a udev rule. And you can change it on the fly with a script if needed.

Udev rule:

KERNEL=="card0", SUBSYSTEM=="drm", DRIVERS=="amdgpu", ATTR{device/power_dpm_force_performance_level}="manual", ATTR{device/pp_power_profile_mode}="0"

(you might be able to leave the power_dpm_force_performance_level part unset)

You can also try the compute (5) or VR (4) modes which have slightly different behaviour (I use the compute mode on my systems even though they are mostly for gaming).

I believe some of the third party GPU control utilities can also do this, but I don't personally use them.

Linux currently doesn't have a concept of "exclusive fullscreen" in the way that Windows does. A new wayland protocol can probably resolve this, although I'm not sure if any work has been done for that yet.

You could do it manually though most likely by having a script check if the current window is fullscreen (which you can do with sway/wlroots easily at least) and then apply the change. But there would be some false positives where you might not want the behaviour (like a video player), although if you're watching high resolution/high framerate content it would be useful.