Vyxal, 4 bytes

Þė↑Ṙ

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And they said maximum by tail was useless! Now who's laughing! (me... It's me who's laughing)

Explained

Þė↑Ṙ­⁡​‎‎⁡⁠⁡‏⁠‎⁡⁠⁢‏‏​⁡⁠⁡‌⁢​‎‎⁡⁠⁣‏‏​⁡⁠⁡‌⁣​‎‎⁡⁠⁤‏‏​⁡⁠⁡‌­
Þė # ‎⁡Multidimensional enumeration
 ↑ # ‎⁢Maximum by tail 
 Ṙ # ‎⁣Reverse the list to meet the output format requirements
💎

Created with the help of Luminespire.

Vyxal, 3 bytes

Þė↑

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And they said maximum by tail was useless! Now who's laughing! (me... It's me who's laughing)

Outputs [[x, y], item].

Explained

Þė↑­⁡​‎‎⁡⁠⁡‏⁠‎⁡⁠⁢‏‏​⁡⁠⁡‌⁢​‎‎⁡⁠⁣‏‏​⁡⁠⁡‌­
Þė # ‎⁡Multidimensional enumeration
 ↑ # ‎⁢Maximum by tail 
💎

Created with the help of Luminespire.

Vyxal, 42 bits^v2 , 5.25 bytes

fG~Þḟ"

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Bitstring:

011101101010110011101000111101110111010000

Explained

fG~Þḟ"­⁡​‎‎⁡⁠⁡‏⁠‎⁡⁠⁢‏‏​⁡⁠⁡‌⁢​‎‎⁡⁠⁣‏⁠‎⁡⁠⁤‏⁠‎⁡⁠⁢⁡‏‏​⁡⁠⁡‌­
fG # ‎⁡Find the biggest item in the flattened input
 ~Þḟ # ‎⁢Without popping, find the multi-dimensional index of that in the input
💎

Created with the help of Luminespire.

Vyxal, 4 bytes

Þė↑Ṙ

Try it Online!

And they said maximum by tail was useless! Now who's laughing! (me... It's me who's laughing)

Explained

Þė↑Ṙ­⁡​‎‎⁡⁠⁡‏⁠‎⁡⁠⁢‏‏​⁡⁠⁡‌⁢​‎‎⁡⁠⁣‏‏​⁡⁠⁡‌⁣​‎‎⁡⁠⁤‏‏​⁡⁠⁡‌­
Þė # ‎⁡Multidimensional enumeration
 ↑ # ‎⁢Maximum by tail 
 Ṙ # ‎⁣Reverse the list to meet the output format requirements
💎

Created with the help of Luminespire.