To get to retina quality you would be shopping the displayport/thunderbolt 4 and 5K displays.
https://support.apple.com/en-us/HT206587 has a list but not one hit 300 bucks.
You may be unicorn hunting this time.
I have a new macbook pro and looking to purchase an external monitor to use with it. I'm looking for a monitor ranging from 21-24" with use limited to general web surfing, occasional video viewing, i.e. YouTube or social videos, and use of Office products like Word and Excel. I also do some very minor photo editing, but this usage is exclusively for personal use, no video editing, no video game playing or anything that requires excessive usage - maybe 4-6 hours use per week.
I'm looking for a monitor with video quality that isn't too much worse than the macbook retina display, with above average audio and an HDMI connection, priced below $300.
Any recommendations welcome.