So I would be glad if some of you can answer me what to say to this guy:
He was acting very rude in comment section because "no one was capable to deny his proofs" - like he said.
For acting very rude there is no excuse.
Saying those are "his" proofs is not quite correct.
Proofs are facts and they don't "belong" to someoune.
All you have to do is to find facts, understand them, and present them.
BTW, Biblical cosmology was based on Geocentrism, not on Flat model.
I could debunk every single globe Earth video except this one.
I don't "believe" the Earth is globe shaped, I know it.
My knowledge is based on observations and measurements, some of which I made myself.
For example, distance to Moon can be easily measured in two ways: radio waves and lunar parallax.
(Sextant can be as low as $30 on eBay.)
Yet, I'm not saying that "I can 'debunk' any flat earth video".
Another question would be, will you 'debunk' it by presenting counterarguments, or by trying to discredit it.
For example, I wonder what would you have to say about this one: