External GPU considerations

Hello fellow gurus,
Lately I realised that I powered up my main computer so little, that feels like that I don't really need it. For the moment I do need it, but later down the road, I could get by with something smaller, with lower power consumption.

And upgrading feels like a joke, prices too high, lots of issues with new hardware. It's a feeling, may not be exactly the situation.

Now, the only thing I would upgrade is a new laptop, with newer CPU platform. Recently, I bought a second hand Thinkpad T480 mint condition with 300€. Does whatever I need, but gaming.

So, I have a RX580 in my main rig. What solution do I need to use with my current laptop?
Is it an external GPU, right? Does anyone has one, can share tech specs, what to look for, cables, interfaces, protocols, the works.
Wonder if it works under Linux, too.

And an external GPU can be upgraded as a normal one? So that's another thing I have to take in account for the long run, as I dislike to buy twice. เล่นUFABETเว็บหลักอันดับ1