Being properly fit has nothing to do with handicap. Don't go into a fitting needing T150s. Go into a fitting to be fit in the correct club head for your game. If that's a T350 so be it.

A proper fitting will fit you club head and shaft to your swing to get you close to ideal launch, spin, ball speed, and landing angle numbers. If you're going into a fitting saying I only want the T150, then just stick with your T200's. If you only are going to get new ones for the sake of saying I'm good, I play T150 irons... then just buy them off the rack.

Handicaps are an indicator of your score, not how well you do or don't hit your irons. Iron play is my weakest part of the game but my 10-14 handicap is more the result of smart, conservative play and keeping the drives mostly in the fairway. A good fitting will determine which irons best serve your game with you giving feedback to the fitter as to your miss tendencies. If your iron play suffers from off center strikes, maybe the new T200 will be better. Lots of people are now being fit for blended sets so that is an option too. With fitting fees being applied to the purchase of the irons, the fitting is basically free so my take a chance? If you are going to invest in new irons, you want to get it right the first time. Best of luck and hope you love the new set.

Handicap is the summation of your entire game. Likely a 20 handicap has enough flaws that the T150 will not help their game. Regardless of driving off course or averaging 40 putts, your skill at consistently striking the ball with a center strike is a better predictor of which iron to choose. There can be other variables like launch angle and swing speed that preclude the T150. Absolutely get fit with an open mind what works best for your swing.
There is that status thing to move up to a club associated with better skills. A case where don’t write a check your body can’t cash.

There’s no specific handicap meant for these clubs, like some magic number that’s qualified you to hit them. Look more at what you’re trying to improve in your irons. How is your distance and consistency? What about shot shaping and over all feel? Decide which is most important to you and move from there. There are 15 handicaps that are excellent ball strikers and there are 5 handicaps that are just really good with their wedge and putters. T100 and T150 lofts are much weaker than T200, so if distance or a bit of forgiveness isn’t something you need and you can hit the center of the face about 80% of the time, they may be for you!

I've got t150 2021, thay are amazing irons, I went from ap2 712's to these, I find them very easy to hit, very strong ball flight, great feel and workability and stop really quickly, I personally play off scratch but would say they would suit anyone that can find the centre (ish) part of the clubface, I have t200 in my 4 iron, that is really easy to hit, you don't lose a great deal of distance even with an off centre strike, combo set of irons all the way for me ! We all need a bit of help sometimes
Hope this helps

Sorry, meant t150 2023 !