If you still need help locating and restoring a recent backup of your Quicken data file, I'd say it's time to call Quicken Support on the phone and request help. Let them do a screen share session with you to review the situation on your computer, to determine the nature of the problem and to figure out how to fix it.
Quicken Support:
Filtered register? Unexpected register sort order? "Missing" data?
Please review https://community.quicken.com/discussion/7181795/faq-register-messed-up-missing-transactions-or-not-showing-transactions-as-it-used-to