Why is wordpress suddenly stripping away all newline characters and how to disable this?

I’ve spent about 3 hours trying out various functions to figure out why the newline characters are being removed every time I save.

How do I figure out why is wordpress suddenly stripping away newline characters? I have not installed any plugins. How can I get newline characters to show up on my site without converting all blocks to HTML and modifying everything in code?

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Author: Mugen