I can understand your frustration, extra work, time, and expense, that it takes to compete at the top level today, on top of the regular hard training and diet.
The stretching is definitely good advice, especially as you get older.
I find a leisurely pre workout stretch, either before or after warm up to be very beneficial. These are very light relaxing stretches, for the entire body, just to release tension and feel good. No harsh stretching, long up to 1 min or however long you want as long as it still feels relaxing and pleasurable. They can also be done anytime during the day. Great for posture too.
If you want to go more intensely into a stretch only do it after your workout, even then don’t force it should still be relaxing.