There’s no denying that James Joyce is an enigma. This excellent review by Mike Aquilina of the even more excellent book by Fr. Colum Power sheds more light on this murky subject than most:
https://angelusnews.com/arts-culture/james-joyce-a-portrait-of-the-artist-as-a-lapsed-catholic/?fbclid=IwAR3ZSJObjaBYDorIkrowIRKokSAwZ74ZLsxpH4dwqqjDXbyt4-HwLnKlMeM