[BipolarBob]

There’s no birds on Mt. Everest or K5. So the tallest mountains were too tall for birds but visible from the right angle.

[AndyTheBear]

Sure I guess maybe the mountain tops he saw were not habitable or maybe they were. I don't know how tall the mountains that Noah saw were for sure.

But the mountain tops were still certainly part of the surface of the whole Earth taken in a strict sense. Thus we know that at least in Genesis 8:9 the phrase was not meant in a strict sense.