another one is KB4012982. if you are still getting it you may have to reinstall windows and install updates one by one until you find it. Not sure but I think monthly rollups are cumulative so the nag screen would be included in every rollup since the first one that included it (April 2017). You can find "security only" updates though which don't have it. There is also the "zeffy patch" that allegedly disables the nag screen but I've never used it so can't comment.
Usual disclaimer that windows 7 is out-dated and blah...