Glitchy Screen - MacBook Pro (15-inch, 2017)

The picture you posted looks good so that would indicate a hardware issue with the laptop's built-in display. You can connect an external display to see for yourself that the issue only affects the built-in display. You will need to have the laptop repaired by Apple or an AASP.

I honestly cannot see any issue myself. If you see an issue with the external display as well, then it is most likely a settings or software issue with the laptop.

Try booting into Safe Mode to disable most unnecessary & third party startup & login items.

Try creating a new user account. Log into the new user account to see if you still see the issue.

These steps may help to narrow down the problem.