UColor A17

As an owner of 15.6 4K - I fully agree with you. Even FHD will be good for 15.6.

I can give you an advice - stay away from 4K 16" monitor. I have one (4K 15.6") and it's sitting somewhere in the drawer. Not used anyore. Although IPS matrix was great (from uperfectmonitor, their first 4K 15.6" product), I can no longer find any use for it now. For a text - it's too small, if you increate font size...you have big font on small screen. uperfect released some 22/24 4K recently, and that's the size I would recommend for 4K, so you can saely go with 15.6 but only up to FHD/QHD, not 4K.

I use a uperfect 15.6 4K and it's a great second monitor for my ipad pro. Charges my ipad, quite a bit more resolution than the one you linked.  Currently running the updated ipados 26.1 which has some bugs but makes the combo very productive. 

Yes its single cable and powered by my ipad. But I usually use the second usb c port to add external power so it charges my ipad instead of draining it.

I use a vertical monitor daily for code and documents, and getting the right size makes a huge difference. For a dedicated vertical display, the [Dell P2422H](https://www.amazon.com/s?k=Dell+P2422H+24+1080p+monitor&language=en_US&tag=bestdeals202f-20&ref=as_li_ss_tl) at 24 inches is practically made for this - great stand with full rotation and height adjustment. If you want to try portable, the [Uperfect 15.6" 4K](https://www.amazon.com/s?k=Uperfect+15.6+4K+portable+monitor&language=en_US&tag=bestdeals202f-20&ref=as_li_ss_tl) models are surprisingly good for text, though at 15.6 inches they're smaller than your range. Honestly for a permanent vertical setup, a standard monitor with a good ergonomic stand will serve you better than a portable one long term.

espresso but is going to be expensive; or lg gram view+ or the uperfect and get some desk tripod? There's a few refurbished units on ebay selling for 100 bucks for the uperfect 4k 15.6". Kind of a gamble but at that price might as well try one. I ordered two this week waiting on them

How small are you looking for? I have two 15.6 inch monitors from Uperfect and one 10.5 inch touch monitor from Intehill that all have full HDMI. The 18.5 inch touch monitor from Eviciv is mini, go figure. For all of them though, I just use USB-C, since the reference 7900 XTX and my mini PCs have the port.