Good Afternoon, I Am A White Male, 60 Years Old

Good afternoon,
I am a white male, 60 years old and a former competitive power lifter (2 years since last competition and no PEDs). The last 2-3 months, I have found no energy in the gym and I'm doing a volume based program now (moderate weights/more reps). It seems I run out of steam toward the end of the workout (maybe 50-60 minutes) and really have nothing left for the 25-minute cardio session, which happens 4-5 days per week.
I am 6'0" and weigh 255. Sleeping fairly well, though I do wake up 1-2 times during the night due to hip and shoulder discomfort; some adjustments and I fall back into sleep.
Non-smoker, drink 1-3 beers per week.
Thank you in advance!
Brian in Irvine, CA