Japanese characters are actually written left to right, but sometimes the page order is right to left. Writing that you might find on a website, e-mails, and scientific writing is typically actually written left to right. While these kinds of texts may have pages that are ordered from right to left, the text on the pages is typically written from left to right. It is typically only when text is written vertically (yokogaki) that it is written in columns going from right to left, and in that case, the characters are read top to bottom.
Sources:
[1] https://www.lingocommand.com/japanese/writing-systems-explai...
[2] https://en.wikipedia.org/wiki/Horizontal_and_vertical_writin...
[3] I studied Japanese in college lol