That article states a "study in 2017" which it doesn't even properly cite. It's seems to be more of an in-depth analysis of the medical aspect of TOS as opposed to detailing the actual performances.
There's been 17 pitchers who fall under an acceptable age deviation as Archer who got the surgery (age 27+, and I'm being generous giving him the benefit of the doubt comparing him to 27-30 year olds). 5 of them didn't pitch a single inning in the majors after the surgery (~30%). When you widdle it down Age 31 or older, which is the quartile Archer belongs to:
Age 31 or older (7 pitchers):
- 95 FIP- before vs. 113 FIP- after surgery
- 4/7 of them pitched less than 50 innings for the rest of their careers
So most either suffered a noticeable decline in production or they pitched very little the rest of their careers, or both. Josh Beckett and Kenny Rogers were the only ones you can only really make a case for that were the same before/after, and Beckett only lasted 100 innings while Kenny Rogers seems like an extreme anomaly.
If you're age 22-26, it seems like you have a good shot of bouncing back to some extent, but age 27+ seems like you're in the dead zone.
https://blogs.fangraphs.com/thoracic-outlet-syndrome-fells-archer/#:~:text=As%20I've%20written%20before,with%20physical%20therapy%20and%20rest.