@DontTalkDT
There's a pretty stark difference from someone who can accelerate his own personal time 3 times to someone who can literally stop time for everyone. I see no reason his time acceleration technique, which he has never used in-character btw, would allow him to challenge a full time stop. He also hasn't open up a fight with spacetime crush, though he was substantially nerfed in his only serious fight by the fact his regular sorceries would be useless against his enemy, forcing him to rely on Vel and his Great Old One summons, so who knows.
As for the BFR, something like BFR him to a pocket dimension would likely not work, as he could feasibly use Daoloth to break through and return to the real world.
@Burning Full Fingers
"Nevertheless, the likes of you who is nothing more than a dreg right now is not a match of this Michael!"
He immediately materialized <Holy Sword> shining golden in his both hands.
That blade reaching until the heaven was swung to bisect Homura.
――Not a match.
This recognition of Michael was correct.
Even the spirit of the current Homura was inferior, he was an existence that was like the afterglow of the moon that would disappear in the morning.
He had no flesh, not even magic power, just a wraith that was only there.
If he swung the <Holy Sword>, just its wind pressure would be able to blow Homura away.
And after using up some of the little magic power he had his spirit body started to lose even more consistency and become more like air, even admitting someone simply blowing on him would send him flying.
"E, eh!? Why cannot I hug Master!?"
Even when Chikori tried to hug Homura, she was only getting bewildered of her arm that was scratching air.
"The current me is a wraith that will fly away if I'm getting blown. Even the little magic power I carried got completely used up when I took away Shiori. That's why honestly holding Shiori like this is really bone-breaking work here. ――Chikori, I'll leave her to you. Also Vel. Give Shiori something to wear. It's too much for her to keep looking like this."
He could become small, but he would achieve pretty much nothing except slowly waste whatever remains of his magic power and get blown up if Tamura sees him become small and just uses an AoE attack on the area he dissappeared.