https://www.notebookcheck.net/Lenovo-Le ... oc-display
Screen PWM is at almost 22KHz, according to Notebookcheck. They do some pretty in-depth testing on the screens and it's a decent one, if not amazing. The response times aren't great but for a 60Hz laptop panel they're pretty average and you need to go TN or hideously overpriced G-Sync to get response-time focused displays.
In terms of other options, the Dell XPS is way overbudget for your spec requirements, I used to have an Inspiron 7559 which had a spongy keyboard and bad IPS screen (clouding/poor black levels). The successors (7567 and 7577) are much better in both regards and meet your spec/budget nicely.
The other option that reviews well is an Acer VX 15 which is an $800 base option but it's bit "gaming" in terms of styling and size/weight. I was interested in one but they only came with TN panels over here, so I've never seen/used one - unlike the Y520, XPS, and Inspiron options mentioned above. You can certainly configure one with an i7, 16GB, 1050Ti, 1TB/256GB combo and still get change from $1200 though.