WTF UFO BYAKUREN!!! I swear that I've spent the better part of the night trying to freaking beat her with continue spam. Not even once have I gotten to her last spell. I mean WTF. I have so much anger right now, especially on her stupid first spell card which seems to be impossible because there's always a little droplet bullet waiting for me after I dodge those big purple ones. And that third non spell? God that's like auto bomb. Her third spell? God that's also an auto bomb, but I still sometimes die afterward because Byakuren isn't affected by bombs and there is like 0 invulnerability time after the bomb finishes. I can't even do her stupid fourth non spell because I always go stupid and die on a stupid line of bullets, and her stupid fourth spell always catches me with one of those big bubble bullets. God her only trivial spell is her fifth one. Stupid stupid Byakuren...
I assume this is normal.
I don't know if you're doing this, but try to get at least 4 extra bombs during the stage part of stage 6.
During the 1st spellcard, dodge the glowy bullets until the small ones reach you, then bomb, it should clear the card.
1 bomb should be enough to bomb through the 3rd/4th non-spells.
The 3rd spellcard is not as hard as it seems, do more vertical movements than horizontal, or you can just bomb through it though.
The 4th spell, do not stay in front of Byakuren, stay slightly left at first, then bubble bullet comes, go right, repeat. (Did you know the white part of the bubble doesn't kill you?) Try to stay alive, watch in advance for those moving diagonally, you don't have to pay much attention to the bubble bullets since those are aimed. Instead, the mid-sized diagonal-moving ones are much more dangerous. Bomb if you're walled on the bottom.
Then try your best to go through the last two by pure dodging skills... can't bomb through them.