R and T keys make weird clicking sounds

There is an active keyboard service program:

Keyboard Service Program for MacBook, MacBook Air, and MacBook Pro - Apple Support

Print out that page and take it with you when you go for your appointment for evaluation. Understand that, should the keyboard require replacement, it will not likely be a "while-you-wait" or overnight repair. Depending on the sub-model they may have to order parts, and a new keyboard usually means a new upper case assembly

Other than using compressed air to blow out possible crumbs, my best advice is a trip to an Apple Store.