A ranking is not a prize. There is no prize for winning this contest. It says that explicitly, two times, in the OP of the thread you haven’t taken the trouble to read.
The idea that a ranking is a prize so therefore it’s gambling would make every competition gambling. Or an unknown result and a prize equal gambling is even more ridiculous.
Willie Wilson finished a distant 3rd in the 2020 Illinois senate race with 237,699. 3rd is a ranking, so I guess senate races are gambling.
Cuba earned a silver medal in the 2022 U-15 Baseball World Cup.
Unknown result: check
Prize: check
The 2022 U-15 Baseball World Cup is gambling.
Do you see how ridiculous you sound?