Valve is rather confident that it will not run out of stock.
But of course nobody can tell for 100% sure.
Some of the more powerful handhelds are missing OLED/touch pads/back buttons/gyro, and don’t have SteamOS (yet).
It’s all pretty much subjective.
There are other places which sell legit Steam keys with their own discounts, sometimes cheaper than on Steam, so you should really shop around. Isthereanydeal.com is a great aggregating site which compare the prices across all legit sites
Fanatical is selling a steam key for the game at 77% off right now
https://www.fanatical.com/en/game/klonoa-phantasy-reverie-series
I used to be a console gamer, but I shifted to PC gaming few years ago when I realized how fuss free it is to buy games, as well as the huge number of games I want that are not on consoles. Over the years console makers introduced paid online and no background compatibility (like PSVR games not playable on PSVR2) while PC gaming just keeps getting better and cheaper games, so I just sink deeper.
I still play on consoles once a long while for exclusives like Spider-Man 2 on Playstation and local multiplayer games on Nintendo Switch, but not often anymore. These days I just pick up the Steam Deck, press power button and start playing in bed or whatever. I have hundreds and thousands of new games and retro roms on this tiny system that I can bring everywhere literally, it is just awesome. It’s a dream come true.