Today, while watching Netfilx,I heard the phrase "If it's either that or bla bla bla"
I get the meaning but I have two questions:
Can I say "Or it's either that or..."?
Is there another way to express the same idea?

Question

Answer

There is a similar expression that fathers use when arguing with their children:
“It’s my way or the highway!”
( mi manera o la carretera)

Answer

The phrasing is not used often.  It’s typically used in cases where some level of frustration is felt by the speaker.  With people you are unfamiliar with it could be interpreted as rude.  A natural phrasing would be “it’s either this or that”  or “it’s either that or this”.   A preceding word is optional.  “Listen” could be used for emphasis when you want  to emphasize the listener should pay attention. “So” could be used when there has been a discussion of  options available preceding the phrase.   The phrase you are questioning has very nuanced uses in American English.

Answer

"this instead of that" maybe?

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