I'm gonna be the problemXY guy and suggest you get a normal laptop, like a thinkpad T14 and friends, without a discrete GPU and get an EGPU setup; you can get a DIY rig in the $50-100 region, dependent on the interface, and you get a ton of benefits:

• you're not limited to gaming laptops. you can get a laptop that's portable, has a long battery life, and widely available on the 2nd hand market, is easy and cheap to upgrade, fix, repair, etc. everything gaming laptops fucking aren't
• your options for GPUs rise dramatically, including reusing shit you already got laying around
• way, way more powerful than laptop discrete graphics with practically unlimited vertical upgrade options

Not a recommendation, but you should consider a handheld and a non-gaming laptop as an option. Beating the Steam Deck in terms of value is a real challenge, and a dedicated GPU + a decent CPU + 32GB RAM will drive the price of any laptop like crazy. A laptop with a mid SoC, 16GB RAM and 500GB storage is more than enough for everyday stuff and will cost you like half of that, while a handheld might be a better experience for non-keyboard gaming.

you may not need a dedicated GPU, the iGPUs on AMD CPUs have gotten really good lately, like better than a mid ranged dedicated GPU from even 4 years ago.

My laptop has a 780m integrated GPU on its 7840HS cpu, and I’ve been blown away at its ability to run modern games. Like, sure, not running cyberpunk 2077 at max settings at 120 FPS in 4k, but running it at medium settings at 60 FPS in 1080? It’ll do it just fine.

My laptop was a bit pricy, but I did a little searching and saw that there’s something called the GPD WIN Mini, the 2023 model was listed as having the same CPU/iGPU as my laptop and it was listed at 700$. It’s an odd form factor, and I couldn’t see it in stock anywhere.

You might be able to get the kind of performance you’re looking form the iGPU on an AMD ryzen 7 or later CPU, and something without a dedicated GPU will probably be a lot cheaper.

If you don’t mind a non-traditional form factor, as other’s have mentioned, definitely check out the steam deck. It’s very affordable and very capable, and other than the form factor, it is just a computer running Linux. You could even boot other distros on to it if you don’t want to run SteamOS (Valve’s arch derived distro).

Not a laptop, but I found a steam deck with a bluetooth keyboard works well for me. It ranges from $400 to $650 new depending on the model, not including accessories. Though a stand and a bluetooth keyboard shouldn't be too expensive. That said you do have to put up with a smaller screen size and keep track of the keyboard, stand, and possibly a mouse on top of the steam deck itself.

EDIT: forgot to add, depending on your needs you may be able to skip the keyboard. If all you're doing is web browsing and posting on social media you could get by with either the on screen keyboard or the kde connect app.

I would prefer to buy 2nd hand or refurbished

Then the answer is pretty much gonna be "whatever you find a good deal on". I sat on CL for several months before finding a Lenovo Yoga Pro w/8845HS + 3050S 6GB for $275. Dude had no idea what he had.

Secondhand macbook pro with the M2 chip and as much memory / hdd available ; it is said to avoid 8g of ram, I went with 16.

Slap Asahi on it, the latest version plays games quite nicely - and since Asahi is dual-boot anyway, you can try the macos side if something fails.

(Currently Asahi doesn't support m3 or m4 chips. M2 machines should be available at bargain prices, mine new was €1500)

I would prefer to buy 2nd hand

It's going to be hard to give a solid recommendation for a specific used computer. What I would say, however, is check out Swappa and Ebay. Those are my go-to places for used hardware.

What games/graphics settings are you targeting?