How to enforce time limits on Mac with a password?
AFAIK, if you're an adult, your Screen Time settings are controlled by you.  Try setting a Screen Time passcode.  Then, at least, you'll be prompted to enter the passcode to continue using apps during a lockdown period.
If you're a minor and part of a Family (in Apple/iCloud terms) one of the adults in the Family needs to set the passcode (for your acct) from their device.