Well, in the range of $300 to $400 there aren't many options available for a monitor that offers 1440p and 144Hz refresh rate. In this price range, what you will see most of the time is 1080p panels.
In case if you decide to go with a 1080p monitor then you can refer this guide for $300 monitors -
https://monitorsavvy.com/best-monitors-under-300/
Now, as you mentioned that you need a 27" 1440p 144Hz monitor, I assume that your primary requirement is gaming. Around $300 this seems to be the best option:
I have never used any VIOTEK monitor before, so I'm just recommending this based on reviews available on Amazon. Also, I would suggest you read all the reviews by yourself once. It's a 1440p VA panel. You will notice a quite difference in colors and viewing angles if you are coming from a TN panel.
Moreover, here is another option that should work for you in the $300-$400 segments:
It's an excellent option to consider over VIOTEK if you don't need a curved screen. Acer XG270HU is a TN 1ms panel that is pixeled at 1440p. You can expect better response times and fairly good colors.
These are the best monitors that perfectly fit your requirements according to me; also you can read in-depth reviews of them online or watch videos on YouTube for much better understanding.