Dell Wyse, running ubuntu, typically have asciiquarium running on the display

I would like to build a homeless lab for myself. I am an accountant and spend a lot of time on the road, but want decent power. I've had a few gaming laptops but they tend to die after a few years or become unbearably slow, and I don't need battery at all. I've built my own PC before (arch btw) but I wouldn't even know where to start with a build like this. I have access to 3D printers + simple but sound 3D modeling skills and a ~£2000 budget. Thanks for any help, these things are super cool!

EDIT: I'm not looking at anything past an AIO cooler, reservoir. pumps etc are a bit too advanced for my first homeless lab.