05AB1E, 101 bytes

•ÍøλMI;ÌL₂<ý¤•13вAuS×J.•∊×FéÛÍ@ƶ
“¬E|*[óAR{œ₄ÝÑâWʒ$^CÓ%$mÚL—λ˜ÇåðH%,YεƒBJ!§½PΣvʒRþKα₂₁ânΔNθ5¨Ó•øðδÜIå

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Same as my Thunno 2 answer.

Explanation

•...•13вAuS×J.•...•øðδÜIå  # Implicit input
•...•13в                   # Compressed list [8,7,12,3,3,5,3,6,3,0,2,5,6,9,3,9,0,8,9,9,1,1,1,1,2,2]
        AuS×J              # Multiply elementwise with the uppercase alphabet - the first letters
             .•...•        # Compressed string of second letters, or spaces where N/A
                   ø       # Zip with the first letters and join each pair into a string
                    ðδÜ    # Remove whitespace (the space fillers in the second letters)
                       Iå  # Is the input in this list?
                           # Implicit output

05AB1E, 100 bytes

•ÍøλMI;ÌL₂<ý¤•13вAuS×J.•∊×FéÛÍ@ƶ
“¬E|*[óAR{œ₄ÝÑâWʒ$^CÓ%$mÚL—λ˜ÇåðH%,YεƒBJ!§½PΣvʒRþKα₂₁ânΔNθ5¨Ó•ø€áIå

Try it online!

Same as my Thunno 2 answer.

-1 thanks to @KevinCruijssen

Explanation

•...•13вAuS×J.•...•ø€áIå  # Implicit input
•...•13в                  # Compressed list [8,7,12,3,3,5,3,6,3,0,2,5,6,9,3,9,0,8,9,9,1,1,1,1,2,2]
        AuS×J             # Multiply elementwise with the uppercase alphabet - the first letters
             .•...•       # Compressed string of second letters, or spaces where N/A
                   ø      # Zip with the first letters and join each pair into a string
                    ۇ    # Remove whitespace (the space fillers in the second letters)
                      Iå  # Is the input in this list?
                          # Implicit output