This is what the new Steam Deck console looks like inside. It has a nice cooling fan for the GPU, but I doubt that the SSD is exchangeable for a bigger one.
Apparently, it has an M2 slot to allow upgrading the SSD if you are careful. M.2 format is technically a replacement for the mSATA standard, which was popular with manufacturers of super-compact laptops and other small gadgets. This is very good I guess, you could purchase a new SSD using that form factor and then install it to the device to add more storage space. Installing Windows on a Steam Deck is possible, but voids the warranty and may not be the best idea. Linux gaming has come a long way and it works very well now. However, if you are looking for a Windows solution then you might want to consider a dual-boot solution and SteamOS on a PC. In order to have SteamOS on the same machine as Windows, you will need to install a third operating system to handle games, and the one you will probably want to use is Ubuntu. You will be able to play Steam games on Windows using the Steam for Linux technology. If you are a Linux veteran, then you will also have the option of installing SteamOS on your system. That way, you can start using Steam OS while keeping Windows OS. There are also dedicated Steam machines that allow you to stream Steam games from a computer that is in your living room. The SteamOS gaming experience has many improvements over other operating systems and games. Most of these improvements come from the fact that Linux is open source and can be customized. That is why it is able to achieve this. The customizability of the operating system is a big advantage to gamers. With Steam OS, you will also have access to the Steam marketplace. You will also be able to easily stream to Youtube or Twitch using OBS Studio.
But the Steam Deck looks like a very handy gaming machine for a gamer on the train or plane. I don’t think phones will be passively cooled for much longer, companies have started adding heat pipes over the last few years, the move from plastic frames to aluminium is also to get rid of all the heat the chips are producing also. there’s even been a few gaymer phones with fans in them recently too. But even if they were, that means there’s still a lot more heat that needs to get dissipated before the case even gets hot enough for the fans. Even if your phone is not using fans so you won’t be throttling it down, the fan still puts out more air than the heat pipe, which makes the phone still cool on average. So you are really looking at a fan with a big enough output to let the air out through the tiny door. For reference, your phone normally runs about 65wh per square meter (about what it is at the time you are checking this out). And the last thing about your phone being passively cooled is that you could get a phone without a cooling pad in it too which will cause a thermal shock that could shut the phone down at any moment. So the best way to deal with this is to get the coolest phone case you can find and use some liquid cooling instead of a passive cooling pad.