End of life as in? Battery not keeping a charge? Joystick drifting? USB-C connector messed up? Most of those problems can be fixed, ifixit has the parts and great walk throughs. Just fix it and keep playing what you like how you like.

Out of curiosity, what games do you play other than Cities Skyline?

If you just want something for portability + ten minutes of gameplay, what about an android phone you can emulate on + one of those phone controllers that turn your phone into a portable console?

The only reason you should buy a Switch is if you have no self respect, don't give a shit about being in an abusive relationship with Nintendo, and don't care about sending thousands of dollars to a company that hates you to get an artificially limited device, and absolutely MUST play Nintendo first-party games, in the intended fashion.

The Deck is such a better device in nearly every way.

Steam Deck is great but keep in mind it's way bigger and heavier than the Switch Lite. If you move around a lot, it's not something you can just toss into a backpack.

What do you mean by "end of its life" ?

Deck is much larger and heavier.

Obviously it depends on what games you want to play.

The one point I will mention in the Switch's favor is that I feel like it's a much better handheld. It's a lot lighter and I like the feel of the JoyCons better (or I did until mine went bad, we'll see how durable S2 JoyCons are). Still, both are ultimately too bulky for me to take on the go, instead I bought a Miyoo Mini Plus on sale and that's become my portable while the Deck gathers dust and the Switch no longer leaves the dock.

If you want to stay in the Nintendo eco system (or at least have no issue with that), the Switch 2 would be the better choice - better hardware, more options with the mouse feature and placing on a TV or display, etc.

If you want to be more flexible, like tempering around with a bit of config stuff and game / graphics settings, controller layout, etc. then I suggest the Steam Deck. I can honestly say that it's a lot of fun. Non-Steam games are sometimes tedious to install and configure Proton with the right version of proton etc, bit you don't have to do any of that, it's just options that come with the device.

If you don't care about Nintendo games. Go for the deck 100%

Biased because I'm pro steam deck, but yes, Steam Deck will offer you the full steam library of games, on top of games from other platforms / consoles through emulation

This was the main selling point for me

You’ll be happier in general with the Deck I think unless you care about Nintendo exclusives

I love my Legion Go. Solid screen. detachable joycons. Standard Win11. It plays things like Satisfactory and RDR2 real well. Ok batt life. Meh speakers. use bluetooth.

A Deck will likely be a better purchase for you. Shared library, more sales too. The Cities Skylines situation you’ve described would have been enough to make that decision for me

If you already have a decent PC for games a Switch allow you to play more games.