Nice thread. For a brief period in grad school I was nerdsniped by Brouwer intuitionism and wanted to dive deep, but then realized it’s sort of a lifetime deep dive sorta thing.
L. E. J. Brouwer (in his 1908 opening salvo against David Hilbert's mathematical formalism and the Law of the Excluded Middle) is clearly channeling Schopenhauer
I know very little about it but there's something in there that keeps me coming back! Did you end up coming to any insights? Are you interested in the realism question?