I never was a Courier fan, but he was mentally a rock, was a tremendous competitor on court and fitter than any current player aside from Djokovic. Peak Courier beats Alcaraz, Rune and Sinner (at their current levels) on every surface - easily.
Oh - and for those thinking he couldn't play on grass and Alcaraz might beat him, Courier played Pete close in their Wimbledon final. A few points either way in the first two TB's and he would have defeated peak Pete on grass. scoreline for Sampras was 7-6, 7-6, 3-6, 6-4. That was much tighter than any score Andre produced against Pete at Wimbledon.