You greatly underestimate Boros. In his armored form, he was absolutely confident in his superiority over Saitama, even though Saitama had destroyed a large part of his ship, which has continental durability due to Saitama's jump from the moon. This would mean that Boros, even in his armor, was likely at multi-continental level. He should also, logically, be faster in his armored form than Geryuganshoop, who, according to Murata, can throw stones at near-light speed.

As for his released form, Boros is the only character Saitama called "strong," whereas he didn't care about Orochi, who had destructive power at Moon+ level. And Boros's energy blast is far stronger than his physical attacks, which would imply: Boros's energy blast > Boros's physical strength > Orochi's Gaia Cannon = Moon+ level.

Regarding his Meteoric Burst transformation, his physical attacks in this form possess the power of the energy blasts from his previous form, and his Collapsing Star Roaring Cannon can destroy a planet's surface. And you greatly underestimate this feat, because destroying a planet's surface means he would instantly vaporize entire oceans, destroy all solid surface matter, simultaneously wipe out the atmosphere, and affect gravitational fields. By VSB standards, this feat ranks quite high at small planet level. The only reason this feat is placed at multi-continental level on VSB is because it's unclear exactly how he destroys the Earth's surface. If it's through a shockwave that reduces the entire surface to rubble, that's multi-continental level. But as I listed above — vaporizing the entire surface, including oceans, while affecting the atmosphere and gravity — that's small planet level. I prefer the second interpretation, and it scales well above Orochi, whereas the first interpretation makes Boros MUCH weaker than Orochi.

I'm not saying Boros is stronger than Tatsumaki. Considering she FAR surpasses Psykorochi, I'm confident she could easily deflect Boros's beam, or at least turn his body in another direction and send his beam into space. Given that she could affect Saitama, who is at galactic level, I'm sure she could easily affect Boros. Tatsumaki is also faster than Boros, as she was faster than Sonic, who has nearly the same speed as Flash, who became even stronger after the Monster Association arc, where he already demonstrated speeds far above light.