It’s true that the feature is currently disabled, but the customer support can restore it for you. However, you need to get lucky to get somebody willing to help you.
Here’s a thread from a few days ago: Accidently deleted main - Support / Customer Support - World of Warcraft Forums - https://eu.forums.blizzard.com/en/wow/t/accidently-deleted-main/525277
A person in the thread successfully got their main back through a ticket. Make a ticket, request them to restore it for you politely, and hope for the best. Good luck.