I turned 71 TODAY (😉), so I can't really comment on the OP topic, but I'll share anyway. My 69th year was my biggest noticeable physical degredation, so I'm in my 2nd year of adaptation to my new normal. I don't do much stretching and I should because the biggest diff has been the limited shoulder rotation. Ball striking has become better with hybrid/flat-bottomed irons, and I remain fairly proficient with wedges, bump and runs and putting. My driver swing is limited but accurate, yeilding me about 180y on average.
Once you accept the limitations that occur, play the appropriate set of tees, find a fun group of buddies, golf is a blast. I've still got 4 years to 75, and am hopeful I can continue to adapt to what happens as I age.
Many of the guys I play with are in their 80s, and it's obvious that they once had beautiful form. Their swing is very good but just shorter and they find a way to score well/enjoy. They play the most forward tees.
My observations: check the ego, play it forward, keep it in play, ride the short game, tinker with equipment, enjoy the camaraderie. 😊
Note: I've had a total shoulder replacement, both knees replaced, lumbar disc repair, and a nerve ablation in my neck. On any given day, it's an effort to begin movement.