> As a teenager, while auditing Kant’s lectures at the University of Bonn

This is not correct. Kant never left the vicinity of Königsberg.[1] Instead, Beethoven was briefly attenting lectures by Eulogius Schneider.[2]

[1] Here is a map: https://www.online.uni-marburg.de/kant_old/bilder/planstrk.j...

[2] https://en.wikipedia.org/wiki/Eulogius_Schneider