I love my steam deck and I think the summer sale is a great deal for it. I would definitely recommend it, to try and alleviate your worries, it is confirmed that the steam deck two will not be out for at least another 4 years. Also, the other commenter said something about the lifespan lasting a short amount of time, that is highly unlikely. It can run almost any PC game, and there is no way that Valve won’t continue to update SteamOS; on the off chance that they did stop, you could switch to a different Linux distro anyway, but like I said it is close to impossible that that would happen.