Since they do sell to some parts of Europe you should have no trouble finding a reseller that ships to the rest.
There are guys on the Swiss classified sites who claim they'll order for you (at a noticeable premium of several hundred CHF) but that Valve will ship "gifted" decks direct to recipients in Switzerland. I do not think this is true. I cannot personally do this with my Irish account.
I was considering getting one next time I go back to Europe for a vacation but even there it's a many months waiting list. Sure, I could get one second hand but I decided to jump off the hype train instead.
It's a bit more work to just pull out and play - I need to turn on the laptop too, such effort!
I forgot to mention in the original post - I thought I was going to only be able to use this in places with really fast wifi. But it turns out I can just turn on a 5g hotspot on my laptop and connect the tablet to that. As long as I'm in the same room, it's fast enough for the max quality settings in Moonlight and I get around 10ms latency.
So it's not as portable as a Steamdeck. But it is "fits in a backpack" portable.
There are mail forwarding services and unofficial resellers. Even in Russia, you can buy Steam Deck with next-day delivery. At a premium, of course, but it's not that bad.
How do you stream?
It's still an absolutely amazing piece of hardware. So definitely play around with it, if you ever come across one.
I have a Gamesir X2 Pro on a Samsung A7 Lite 8.7" that cost me about $150 to put together.
The X2 Pro doesn't normally expand out that far, but you can take a pocket knife and just cut off the two clips preventing that expansion. Super easy to do. The only down side is the USB-C passthrough charging doesn't work.
I also use moonlight, but the best part is installing PSPlay and connecting to my PS4 Pro. That gives me the suspend/resume/sleep capabilities that make the SteamDeck so popular for quick sessions and Ghost of Tsushima on this setup looks unbelievable for a 6 year old console.
It is also 100g heavier, but you seem to be used to that. And on the A7 at least, the gamepad blocks the headphone jack so you need to use bluetooth.
Now the issue here is that I am trying to boycott Steam, what kind of open source support is there for Valve's hardware : Steam Link, Controller, Deck, whatever their VR headsets are called ..?
[0] https://www.phoronix.com/news/Steam-HID-Steam-Deck-Linux-6.3
However, the frustration led me to discover something even better: it's possible to stream games to a tablet from my laptop (which is way more powerful than a Steamdeck).
So I bought a a clip on gamepad and attached it to a 10 inch tablet. The weight comes in within 10g of the Steamdeck and streaming over Moonlight is surprisingly easy to set up. Parsec is another app that looks interesting and you'll need to use that if you have an AMD card.
So now I can play an a super high quality 10 inch screen with zero fan noises and hours of battery life. I've played through most of Stray and it's a gorgeous game.
I still need to do some work - the gamepad I bought (Ipega 9083s) clips on quite low on the tablet which makes it a bit top heavy. It's also very cheap and the d-pad is a bit crappy. Neither is a deal breaker for a casual gamer.
However in the future I'll get a better quality gamepad. There's surprisingly few that can attach to a tablet but I've seen examples of people DIYing it with a Razer mobile gamepad that is designed for a Samsung Galaxy and it looks pretty easy. You can probably just detach the two halves and glue them onto the tablet cover in a stylish looking way if you have decent DIY chops and a dremel.
Oh and you'll also need a HDMI dongle to create a fake screen on the pc, then give it the same resolution as your tablet. These cost about a euro.
Bonus: I now have zero interest in buying a Steamdeck.