One thing that will be the biggest general qol for your new build is likely to get a M.2 NVMe for your games and OS

Civ 6 is pretty flexible and dwarf fortress will run on a potato, basically anything remotely in the gaming market will play them fine. Civ 7 is more intense, but being turn based cpu tends not to be the bottleneck

Do you have any preferences (distro, cpu/gpu manufacturer, etc) and a budget? Most of the games on your list I am familiar with and will run on damn near anything remotely modern.

Lacing direction, with the fairly low requirements (from what i recognize), and assuming you are price conscious id suggest you poke around the used gaming PC market (either gamer friends, or failing that online), which will also completely bypass the tariff issue too.

PopOS is pretty solid for linux gaming and has a distribution specifically for Nvidia too which handles most of the headache with Nvidia if you go that route.

EDIT: Poked around the requirement pages of the ones i wasn’t familiar with, i didn’t see a single game that had a requirement of anything newer than 10 year old hardware, depending on your friend network, you could get a computer that could play those games well for a song. Civ 7, your ‘evenutally’ game, is the only thing listed that has strongish requirements, and would be what i would pay attention to if you are aiming higher.

Whats your use case?

Was somewhat recently considering a linux laptop myself and ended up deciding the steamdeck fit my needs well.

A dock + portable keyboard & mouse for when i need to do typing or w/e, and a fun handheld console for when i want fun.

That being said, depending on what your “older” laptop is, it might not actually be much stronger, or it might be wildly overpowered for what you need.

I wonder if the steam deck will work for you. Its sacrifice of physical keyboard for portability will probably be the deal breaking issue if I were to guess, but not sure. I’ve seen plenty of people use them as computers for various field projects not game related. It’s cheapest is 350 if you don’t need a lot storage on the device and the storage is upgradeable. It’s compatible with normal USB c hubs for if you do need a physical keyboard or w/e. There are definitely some hangups that may make it undesirable and from what you described some of them are definitely possible, ie if you want to pull it out in the field and do a lot of typing without setting up a dock and whatnot, it won’t work for your needs. But if the fieldwork with it is mostly just start a program and connect a USB data source, and most typing will be somewhere with a desk (home office or w/e) then it may work.

I was personally looking for a Linux compatible laptop a while back (admittedly I asked the wrong community), and eventually came to the conclusion that my wife’s steam deck was actually a great solution for my needs, the main times I needed a keyboard I could just setup a simple dock and plug one it (though if you get a USBC or Bluetooth keyboard the only use for the dock is for holding it upright or additional peripherals), and most of my on the go use of it doesn’t need a lot of typing.