I had a similar predicament although my work laptop is windows rather than the 13" MacBook Pro that I use at home. My IT department told me that my Dell Windows 10 machine wouldn't output in 4K so not to bother spending the extra although I'm not 100% convinced and not sure how to check for sure? However they did make a good suggestion about Ultra Widescreen monitors as I like the dual screen setups in the office. Windows 10 allows, without any additional software which can't be loaded onto my locked work laptop anyway, to split screens so two side by side pages look normal and also without the bezel borders of two separate screens. Excel spreadsheets show an awful lot of columns when in full screen mode even without the 4K resolution.
The cheapest Ultra Widescreen I could find at the time was this one;
https://www.box.co.uk/LG-34WK650-W-3...hoCX-EQAvD_BwE
although it was only £290 but prices of home working equipment have been jacked up since lockdown began.
I did buy the 29" version beforehand but sent it back as it had a screen flicker and it wasn't height adjustable which is big no no as I found out being hunched over it all day. Strangely it also seemed quite small too. The 34"version still only has the standard UWFHD 2560x1080 resolution but there's a big jump in price for the 4K equivalents. I've used it constantly for the last two months and it's been a life saver when working from home as, like you, I can't face working from a small laptop screen. I also actually prefer it to my office setup of dual 23" screens too and I would recommend it if you have the desk space.