Something with a spacious keyboard would be great.

I bought a used HP Elitebook on eBay for a similar purpose. I can browse and do video calls on a bigger screen when the fancy strikes. Pretty much any used business laptop should work. I think I paid about $300 for mine and I paid extra for particular hardware I thought was neat but you don't have to. Only thing to keep in mind is the battery will likely be pretty worn.

I went with a used ThinkPad yoga 370. It still only has a dual core while the following Gen has 4 cores, so it seemed there was a price gap. It has thunderbolt 3 for when I want to switch to a bigger screen (with a cheap USB c dock) and USB c charging. Also I wanted to try a touchscreen on a laptop. I should be able to upgrade the single ram stick in it at some point. Running arch with sway without problems.

Edit: I had a x240 for years before. It was fine but I appreciate the higher resolution of the 370, even if I ended up using fractional scaling as it was just a bit too small.