What is the most "heavenly" music you 've heard?

Miserere mei, Deus
Miserere (full title: Miserere mei, Deus, Latin for "Have mercy on me, O God") is a setting of Psalm 51 (Psalm 50 in Septuagint numbering) by Italian composer Gregorio Allegri. It was composed during the reign of Pope Urban VIII, probably during the 1630s, for the exclusive use of the Sistine Chapel during the Tenebrae services of Holy Week, and its mystique was increased by unwritten performance traditions and ornamentation. It is written for three choirs, two of five and four voices respectively, with a third choir singing plainsong responses, each singing alternately and joining to sing the ending in one of the most recognised and enduring examples of polyphony, in this case in a 9-part rendition.
- Came here to say this
  +1

Peppino D’Agostino - Closer to Heaven
Samuel Barber - Adagio for Strings
- Adagio for strings usage in the original home world game was one of the most impactful moments in entertainment for me across all mediums.
  
  This is exactly what came to mind when I read the question. Unbelievably cinematic moment. Still one of my favorite strategy games.

Warszawa by David Bowie sounds like if heaven was really sad for a day. But still heavenly
- I'm looking for warmer if that makes sense but i will check it out nonetheless
  What do you think of Moss Garden?
  
  I haven't gotten around to listening to all of Heroes yet so I'll have to get back to you on that. Thanks for deciding what album I'm gonna listen to first today though lol

https://youtu.be/W29zEuZVaxs
Dimash* Qudaibergen's high end is downright angelic during the climax of the song.

Creating God - Avenged Sevenfold
...I think it's actually about AI, but this is about as theistic as it gets on my personal playlist.
Shockingly prophetic for something from 2016 - as far as our usage goes, it nailed it.

Guess that kind of depends on whether you're going for "sublime serene harmony" or "the unfathomable might of God". I think the church kinda nailed it on both fronts, choirs for the first and pipe organs for the second.
This scene from Mr. Nobody is a great example of the first, which seems a bit more what you're going for.

Requiem for a Dying Planet was the sound scape for Werner Herzog's Wild Blue Yonder. A brilliant film backed by this album, I feel that the album stands on its own.
This recording brings together three very disparate elements into a synergistic whole. They are Ernst Reijseger’s cello, the choral singing of the Sardinian group Tenore e Cuncordu de Orosei and the soaring vocals of Senegalese singer Mola Sylla. Each is a singular expression of music from widely differing traditions; together, they’re indescribable.
Requiem For a Dying Planet is not the anticipated death song for the earth, this music is dedicated to this wonderful planet and the beauty of living which could be heavenly if religions would not exist.”

Well this a oddly specific timed post for me! As just yesterday I was able to have a listen to this badboy from Avantgarde Acoustics company. This is the TRIO G3 and is a horn speaker rather than a "normal" speaker. It was absolutely insane to listen to. You could play it so insanely loud without any added distortion and the clarlity was crystal clear. Hands down one of the coolest - or - most heavenly experiences I've had in a while! Highly recommend going to a local HiFi center where they might have these to have a listen. I'm not an audiophile whatsoever and thought this was by far the best speakers I've ever listened to.