Steam deck (solved. Ty everyone!)

You can save several bucks if you buy the basic 64GB version and install a SSD all by yourself. There are plenty of guides for that process.
I'd check those out to see if you trust yourself to achieve that, But if you have never built anything and can afford to pay more, I'd pass on that experience.

I have the most expensive version and the alternative screen is irrelevant. The special Steam profile theme is nice though. ^_^

Edit:
Here some guides.
https://www.dexerto.com/tech/upgrade-steam-deck-storage-1970144/
https://www.youtube.com/watch?v=vHCKQvyxwiE

I got the 64 GB Steam Deck in March and a (*Edit - just realized I wrote the wrong SD Card) 512 GB SD card from Amazon for about $50 (Canadian) The Deck does not come with an SD card, only the SSD card! The SD card is necessary, I got this one: SAMSUNG EVO Select Micro SD-Memory-Card + Adapter, 512GB microSDXC 130MB/s Full HD & 4K UHD, UHS-I, U3, A2, V30

My games work really well and the only (pretty minor) problem is my Internal Drive in Storage is constantly low, right now I'm at 929 MB/46.5 GB even though I only have about 5 GB of Proton installed in there! There are programs(?) people have made for you to clean out something called shader caches which I believe don't get deleted when uninstalling a game and take up a fair amount of space! These let you delete them manually for each game you don't need that data for anymore! Here's one that seems really good, I've used it once and only took a few minutes: https://github.com/mcarlucci/decky-storage-cleaner

The SSD card upgrade would be for the Internal storage to help you download even more games and deal with shader caches, I haven't replaced the SSD card as it hasn't seemed necessary and it's possible you can cause a mistake! There are video tutorials though and you can get a gigantically sized SSD for way less of the price than the other models of Steam Deck, so even if you took your Deck into some tech store and had them replace the SSD card that comes with the deck with yours instead (they may want you to buy the card at their store...) you will have way better storage and still pay less than the highest model!

I used to play games on a really old laptop, the Steam Deck is absolutely amazing :) I also don't know much about technical stuff, but I've found everything very easy to deal with!

The process of upgrade is pretty simple and doesn't justify at all the price tag. You should buy the 64Gb and upgrade for yourself, then spend the rest of everything you have on games, accessories or other things. I currently have a 500Gb SSD + 500Gb SD and I have everything I need installed there. That's way more than enough to make the thing work flawlessly.

be sure to buy the dock the 1gbps it's a must have

1) Dock is basically a port extender. You can both charge and connect a TV/keyboard/mouse/whatever you want. Do you need it or not? Hell is I know It's very individual. But I advice against official steam dock. There is a shit ton of cheaper and better solutions. Regular type-C hub with charging function will be better both by price and features, only difference is official dock serves as a stand for deck, but I don't consider it a killer feature. I have official one, so I know what I'm talking about. Unlike deck itself, dock is overpriced a lot.
2) Etched screen is anti-glare measure, not physical protection. But do you need a protector... Well, I guess it depends on many factors. I don't have one, and I'm fine (and I'm on more cheap model without etched screen). Also, not directly connected, but... I've had a protective screen on my previous phone, but still break it's screen (obviously, protector also was damaged) - so it's not a panacea.
3) SD card is very individual too. I have a 256 version, and I never felt a lack of space. It's all up to a question of "how many games you want to be installed simultaneously?". Also, I despise SD cards, they are inferior to SSD and cost almost as much. So if I'll ever feel lack of space - I would better change the SSD, than buy SD card. Of course, it's more technically hard, but I believe the outcome is worth it.
4) You didn't ask, but... If you plan to play on deck without connecting it to TV, but from home/yard - I highly recommend getting a bean bag chair. It's literally best accessory for deck!