Which app are you using? Lightroom Classic or Lightroom desktop?
If you are in Full-screen mode in either app (i.e. you only see the image, but none of the side panels) then the Esc key will revert back to normal mode. However, in Lightroom Classic there's a secondary "full-screen mode" which retains the normal display but maximizes it (which involves hiding the bar containing the minimize, maximize and close buttons). That is done using the Shift+F key combination, which toggles between three slightly different states. So try that key combination once or twice to see if that restores the normal display.
I'm using LR desktop that came with LRC and PS monthly subscription. . I tried the Shift F but didn't work.( is the + sign used or are you just say to use the Shift key with the F key?) I also tried uninstalling and reinstalling the latest update but that didn't work. Same with escape. So far the only way to get it back is reverting to the previous update. The brings the buttons back most of the time. Thanks