As someone who routinely used 110ppi and lower external displays next to my retina macBook displays for years, I have no issue jumping back and forth.
Over the last couple weeks, I've been getting acquainted with my LG 32UL500 32" 4k @ 140ppi. Being used to the 'looks like' 1440x900 resolution on my 13" MBP, I find UI elements similar in size at full 4k resolution. The pixels are small enough that they do not bother me. I can drop back into a scaled resolution when I don't need as much content displayed, and it looks fine to me. Looks like 3008x1692 makes for a very nice compromise resolution for me. For an entry level 4k display, I cannot complain. It's a very good productivity monitor.
For the OP's intended use, I would look for a model that is a little brighter and possibly with a higher refresh rate, but I have no hesitation recommending a 4k @ 32" display to anyone.
That variant at Costco looks pretty promising. If you go that right, make sure you have either a USB-C to Display port cable or dongle. I think I've read that Minis can be fussy with the USB-C to USB-C with power delivery connection. While HDMI works fine as a connection, the Mini HDMI blocks the ability to control brightness and the display's speaker volume rendering apps like Monitor Control useless over HDMI.