This is a good candidate for an intro to Rule Machine, as it is both not natively available via any stock app (as far as I can think of), and it would be pretty easy to write. Try something like this:
Trigger events: Time is 10 PM (choose "Certain time" as the capability for the trigger to make this)
Actions to run:
IF (Garage door is open) THEN
Notify: "Garage door is open, but it's 10 PM."
END-IF
To answer a common question when rules are provided in a format like I just did: no, you cannot input this text directly. Rules must be built using the drop-downs and other options in the UI. This is just a easy way to demonstrate what the end result should look like. For example, to create that first "IF THEN," in your actions section, start with "Select an action type to add," choose "Conditional Action," then for "Select Which Action," choose "IF (conditions) THEN" and continue filling in everything you need.
If you're not sure where to find a specific action, the "List of Actions" section in the Rule 4.0 docs may be helpful: Rule-4.0 - Hubitat Documentation (and the Rule 4.0 docs thread that is more or less the same thing is also good reading with more examples and explanations). Also, always use the buttons in the RM UI to navigate, never the "Back" button in your browser.
Hope this helps, and good luck with your first rule!