My two cents:
The seven red bursts represent the
seven seals mentioned in the
Book of Revelation.
The red angels are the
seven angelic heralds of the apocalypse. Their "trumpet" call is what disrupted the Enterprise's systems, because they were not yet ready to receive the word in its pure form.
At first Starfleet believes the apocalypse to represent the end of all life in the galaxy, and indeed it is accompanied by some disastrous events leading up to it, but it will be discovered that it's actually a revelation of knowledge (the other meaning of the term apocalypse) about the origins of the universe, one that ties together multiple faith's creation myths (including the African folktale mentioned by Burnham) across multiple species and bridges the gap between faith and science.
Spock has been hearing the call of these angels since childhood and is the key to understanding them. It's sort of a play off of Sybok's hearing the call of the false god of Sha Ka Ree, but with more benevolent and genuine intent. Michael is going to be a part of Spock coming to a complete understanding of the message in a bottle these bursts represent, repairing their relationship while they uncover the truth.
It fits the showrunner's intention to have this season be an examination of faith.