I have the larger version of that "fan". It's actually not just a simple fan. It's a peltier cooler, i.e. it gets actively cold on one side. I also have the matching replacement rear housing with metal plate that sits over the soc/ssd/etc area.
I removed the thermal paste from the soc and replaced it with Honeywell ptm7950 thermal pad. I then swapped out the thermal pad that sits on top of the heatsink over the soc, and added a thermal pad onto the ssd, then replaced the metal shield that goes over that and contacts all of the pads. I then added a thin thermal pad on top of that shield, which makes it tightly contact that metal plate in the housing.
The end result is that a ton of heat is dumped into that metal plate. Then the peltier cooler magnetically pops onto that plate.
I have the tdp whacked up to 22 watts, the cpu and gpu are undervolted, and overclocked to 4ghz and 2ghz, respectively. With no cooling mods, running Elden Ring at high would get me temps in the mid 90's before the system crashed. With just the Honeywell thermal pad, mid-high 80's. With the hosting with metal plate, low 80's. And with the cooler, mid-high 70's.
I then manually adjust tdp and click speeds in powertools, depending on whether I am docked and using the cooler, or handheld and not using the cooler. With a mix of medium and high settings, Elden Ring is a nice smooth experience, docked or handheld.
And no, I have never burnt my fingerson the plate. Not sure why people think they are going to be shoving their hands half way across the back of the deck while playing, rather than resting their fingers on the back buttons, or holding the grips.
The only thing I still want to do is use a dremel to add air vents to the new back, in the spot where the stock back housing has them. Just need to source a nice bit of metal mesh to install there, like the stock one has.
Was all of this necessary, or even worth it? To me it was. I plan to downsize(and reduce power use) of all of my electronics, and part of that will be dual/triple booting the Deck, and making it my main(and sole) PC. Pushing the Deck as hard as possible, plus adding a dock, cooler, monitor, other accessories, will still use worlds less power than my current gaming laptop and its associated accessories. Even if you add my phone and tablet into the mix.
Only just got my Deck. Still in the process of doing upgrades and mods. But while I have been testing my overclock and cooling mods and whatnot, I have put a few hours into Elden Ring and it's awesome on the Deck. The load times are insanely fast compared to my actual high-end gaming laptop. Looking forward to starting a new save on the Deck, after I have everything setup the way I want it. Waiting on a 2tb ssd to replace the 1tb that I just put in the a few days ago. Need to get that swap done before I can finish the cooling mod.
I've also put a couple of hours into the Demon Slayer game while testing. That game runs at a locked 60 fps, and plays amazingly.