There is not really any such thing as required fields in monday. However, there is a monday marketplace app called “workflow” that seems like it might work for you. (I have not tested it myself yet). It is also possible to control workflow using hidden status fields, conditionally moving items to another group or board and undoing disallowed changes by using the API with custom apps or tools like Integromat.
Jim - The Monday Man channel
Signup for a FREE Integromat account with this link and get a FREE hour with The Monday Man