A terrific article is posted on PGATour.com re Jordan Spieth being fitted to a new TSR2 driver prior to Pebble Beach by Titleist PGA Tour fitter J.J. Van Wezenbeeck.  I believe so strongly in having a professional fitting with a Titleist fitter and this article affirms that.  The same game improving benefits that a Tour Pro sees from a custom fitting are available to everyone.  I was scheduled for a full bag fitting in Acushnet when the pandemic hit.  When a job loss occurred I had to cancel.  Hope to be able to schedule a fitting in MA or CA hopefully soon.   
www.pgatour.com/.../why-jordan-spieth-changed-drivers-at-pebble-beach.html