Is Investopedia wrong about a Collar's maximum loss and profit?
The Investopedia article is correct.

Isn't your maximum profit when P≤77? Then you can exercise your 77P, but the call holder can't exercise his 97C. Your profit =77−P− options premiums.

You haven't accounted for the loss on the stock (Investopedia did).  It is:

stock price + strike price - collar cost (-80 +77 -1.50)


Isn't your maximum loss when P≥97? Then you can't exercise your 77P, but the call holder can exercise his 97C. Your loss =P−97+ options premiums.

You haven't accounted for the gain on the stock (Investopedia did).   It is:

stock price + strike price - collar cost (-80 +97 -1.50)