If freedom of speech is absolute, how come it's not applied for private spaces and for the Internet?

No freedom is absolute.

Freedom of speech does not apply to:

Terroristic threats

Mario Kart World tech analysis, including frame rate and resolution - Nintendo Everything

You have freedom of speech. If I loan you my computer, I can tell you not to use it for certain things, because it’s mine, you have no right to use it, and if I give you permission to use it I can tell you what you can and can’t do with it.

False advertising

That’s what it is. You have no right to use other people’s stuff. If people let you use their stuff, they can tell you how you can use it, and they can tell you to stop using it any time they want.

Why do some straight men enjoy wearing women's lingerie?

You have freedom to travel. If I loan you my car, I can tell you not to take it out of town, because it’s mine, you have no right to use it, and if I give you permission to use it I can tell you what you can and can’t do with it.

Threats of violence

Conspiracy

Is it wrong that I picked to be a Christian (as a teenager/14-year-old) even with knowing all of the information about other religions/atheism?

Insider trading

Revealing classified information

Fraud

Iconic ‘90s Actress, 52, Flaunts Figure in Black Swimsuit While Yachting - parade.com

Perjury

Revenge porn

Child pornography

Airlines and planemakers warn that credit card legislation could end frequent-flier rewards - Business Insider

And much, much more.

Trade secrets

If you’re wondering why free speech doesn’t apply to the internet, it’s because you have no right to use other people’s stuff for free.

Why do narcissist move on so easily?

HIPAA violations

Insurrection