The Hilton is ideal--it's right there and you can take advantage of all airport transportation.
If you have the energy and the desire-- run into Chicago on the train. You would get there probably 5-6 pm. I wonder what would be open at that time that would make it worth your while. If you go into town, I would check out Pizzeria Due. ( A native Chicagoan turned me onto this place). Garrett's popcorn is the best. You can also buy it at O'Hare. (Which is what I would do if you like popcorn and their Chicago mix is wonderful). I wouldn't want to be on the train very late going back to the airport--that's just me.
There is a Harry Caray's that you can take a free shuttle to from the terminal. Harry Caray was a famous Chicago sports announcer. https://www.harrycarays.com/harry-carays-italian-steakhouse-rosemont.html
It's very Chicago sports themed and I've always enjoyed it. I've killed a few hours there with total strangers as well as colleagues. https://www.sonesta.com/sonesta-hotels-resorts/il/rosemont/sonesta-chicago-ohare-airport-rosemont?&c3api=3976,621256976622,sonesta%20chicago%20o%27hare%20airport%20rosemont,e&gad_source=1&gclid=CjwKCAjw57exBhAsEiwAaIxaZpuiqfb58rx271K5friE8-6pC1Cu-QicZr_nwWyhNoSW_toG-Sdg-xoC8x0QAvD_BwE&gclsrc=aw.ds
I haven't been to Chicago since the Pandemic, so alot has changed. If you were arriving earlier I would've suggested renting a bike and going up and down the bike path past Soldier Field, the Field museum, and Navy Pier. I don't think shopping or sightseeing along Michigan Ave is what it used to be. There is some wonderful architecture along Michigan Ave such as the Tribune Tower, Chicago Athletic club and Wrigley building.
Frankly, if it was me, I'd just hang out at the local Harry Caray's and take advantage of the free shuttle back and forth to the airport and get a good night's rest for the early flight out in the morning. Other's that know this area better may have better solutions to your question and interests.