I’m going to use Linux on it (probably NixOS with a Wayland compositor like Hyprland or Niri), it will mainly be used as a social media and surfing machine, intended to replace my phone for something that’s more private and FOSS. So it will go down in my bag to be used on the bus, at work, etc. It will be used in my bed and in my couch. I won’t be gaming on it, but I’d like to stream media from my Jellyfin server. I will then relegate my phone to be used only as a phone and for proprietary banking apps that I can’t avoid.
For reference I am in Sweden, and I’ll probably use something like Tradera. But if there’s any refurbished options within the EU that you can vouch for that’d be cool as well.
To give some examples of what I’ve found:
T450S with a i7-5600U and 12 GB RAM for 2000 SEK ≈ 180 EUR.
L430 for 600 SEK ≈ 54 EUR.
X280 for 3215 SEK ≈ 293 EUR (above my budget, just wanted to include it for pricing reference).
ThinkPad X270 i5-6300U 12, 8GB, 256SSD for 2306 SEK ≈ 210 EUR.
I’ve never really used a laptop before, I’ve always used a desktop, so I’m unfamiliar with what to look out for, how much stuff is worth, etc. I don’t want to be ripped off.
Thanks so much for any help!

I have a T440S with 8GB RAM and a mechanical 500GB that I bought in an African computer shop about 7 years ago. The computer has a Swedish oriented keyboard, but I hooked it up to a big 44 inch HD screen using an adaptive connector. Works fine. I run the latest Debian, with Niri, and I had to configure Out-of-Memory Killer (which was necessary given what I do). I’m saving up for an upgrade, which I should have done a long time ago, but I haven’t thought it through.
Now, based off the information presented, that T450S looks the part. If it has a mechanical drive, I would replace that at some point if needed, but I would likely pick it over the X270 which costs slightly more. The display matters, so you have to see what works for you, given preference. I think the T450S has a bigger display.