Yes, I know that Chat gpt is not a recognized authority. But, the advice is consistent with what I have read in many places, including here on BF. Do you not agree? Then in your opinion, what is the desired amount for someone my age?
Given what I know about you — ~70-year-old male, ~140–142 lb (≈64 kg), serious cyclist, lean and active — your protein needs are a bit higher than the generic RDA.

Your target protein intake

Baseline minimum (RDA – too low for you)

• 0.8 g/kg/day → ~50 g/day
  
• This prevents deficiency, not muscle loss or performance decline.
  

Recommended for you (active, older athlete)

• 1.2–1.6 g/kg/day
  
• That’s 75–100 g of protein per day
  

This range is well supported for:

• Preserving muscle (sarcopenia prevention)
  
• Supporting cycling training and recovery
  
• Bone health
  
• Immune function
  

For someone your size and activity level, I’d aim for ~85–95 g/day most days.