Update - I think I’m nearly there with the solution.
I think I can add an event listener for the Update Record button and then put an extra validation that checks the server time and rejects the update if the server time is outside of the business hours range using a code like the one in this link: Extra form validation after submit?
So now I have only one final question: what is the event listener name for when the user submits the records for update but the records haven’t been updated yet?
I found this listener here: Action Buttons - Update Records event listeners but it won’t help me as it is triggered after the update has been made, and I want to be able to block the update.
Thanks