American novel or short story, maybe by Philip K Dick about an artist who goes on a quest to paint God's face

Question

I haven't read the story, but I heard about it multiple times from different sources. The only problem is, I forgot the name of the story and the name of the author, but I think it was Philip K Dick.

So the story goes something like this: in a post-apocalyptic, dystopic world, an artist goes on a journey to paint God's face. For some reason, he is the only one who can fulfill this task. The world is a desolate place, very much like in The Road. God is a physical entity who resides in the physical world and is more of an evil demiurge than a benevolent divinity.

It sounds very Philip K Dick to me, but I may be wrong.

Answer 1

Almost certainly Deus Irae, a collaboration of Philip K. Dick and Roger Zelazny.

From Wikipedia page:

After 1982, the world experienced a devastating nuclear war. Fallout and radiation has caused widespread mutations to human and animal populations alike. There is a new messianic religion, akin to gnosticism. The members of this religion, known as the Servants of Wrath or SOWs, worship the creator and detonator of the war's ultimate weapon, Carleton Lufteufel (from the German words "Luft," meaning "air," and "Teufel," meaning "Devil"), ex-chairman of the Energy Research and Development Agency of the United States of America - ERDA/USA.

Tibor McMasters is an armless, legless cyborg phocomelus artist who has been commissioned to paint a mural of Lufteufel, though nobody knows where Lufteufel lives, or what he looks like.