Which monitor to buy for web design

Hi. I just started the web design course and currently have a mac book 13" and it’s way to small. Looking to buy a monitor to connect to it so I can still use my laptop on the go and at least have a big screen at home.

Can anyone recommend a good monitor for web design?

What resolution do I need? Full HD? 4k?

What size is recommended? 27 Inch? or is it better to have 2 monitors?

Hi, I spoke to my uncle who works at BH photo, and he recommended this one: https://www.bhphotovideo.com/c/product/1643474-REG/dell_u2722de_27_ultra_sharp_qhd.html
I also think that if you are currently working on a small screen it might be overwhelming for you 2 monitors. (that happened to me…) So I started with one 27" and I’m doing great with it.

Thank you so much! Really appreciate it!