The story
From new + skeuomorphism. A Medium posthttps://uxdesign.cc/neumorphism-in-user-interfaces-b47cef3bf3a6?gi=d16d78e27024 on December 19, 2019 by Michal Malewicz credits the name to Jason Kelley (who spelled it Neuomorphism, on December 3, 2019https://medium.com/@jason_kelley/neuomorphism-2c4cbe84caae).
Etymology from Wiktionary, CC BY-SA 4.0.