…download Celeste-M1-Libraries.zip from here [github.com], unzip it and copy the libraries into the Owlboy.app package overwriting the old libs where applicable.

FNA.dll and FNA.dll.config go into Owlboy.app/Contents/Resources/.

The dylibs from the osx folder go into Owlboy.app/Contents/MacOS/osx/.

(credits to Abe Jellinek for the original celeste fix and for building these libs)