There is a sad history of many tenors who became relatively successful without understanding their instrument. Natural talent can take you only so far, and on days where the voice is not effortlessly responding, you need to go back to the basics which gets the voice in tune and in line. The realization you can wake up in poor voice, carefully vocalize until the voice becomes responsive, is the best form of relaxation. After awhile, the singer learns the vocal exercises which work best for him or her, and the good habits eliminate most if not all of the vocal problems.

I hope you and yours are keeping well during these difficult times. At my Catholic church, everyone except me, is wearing a mask, and all the hymns and mass parts are Ron solos, until further notice!