Netflix has its ups and downs. bu doğru görünüyor mu?

@Kohaku589 I'm afraid to say I don't have a short, reliable answer for that. A lot of it you have to understand case by case.

I'll try to give a few general ideas here.
1) In English, we use a lot of fixed expressions, so these have to be memorized as a unit: "to have its ups and downs", "to grind one's gears", "to scare the living shit out of someone". I feel trying to figure out why it's "one's" instead of "the" takes a lot of energy for little reward. In all languages I learn (French, German, Bulgarian, etc.), I memorize expressions and accept them "as is".

2) "the" often denotes a general concept. Take the expression "I've got the blues". The unit "the blues" represents the general concept of depression and not my personal way of feeling depressed (so "my blues" doesn't make sense).

Applying this to "Netflix has its ups and downs", we're talking about the "ups and downs" that apply to Netflix only. Not HBO. Not the movie theaters.

"Ups and downs" changes depending on what we're talking about. "the blues", on the other hand, is always depression.

3) Often, you need some sort of determiner/article in English to be grammatically correct.

And we can use "the" as long as we are specific enough.

Ex:
You can't write "the ups and downs" and leave it alone like that. My automatic reaction would be:

"the ups and downs (of what?)"

OR

"(What) ups and downs?"

To answer this question, we have to add that extra detail.

So I can say:
- The ups and downs that apply to Netflix only.
(Notice I wrote exactly this in my 2nd point)

Hope this sheds a bit of light on your questioning.