Default and “optimal” views are trash. I want to see 1 page at a time. Setting the zoom to Entire Page puts 2 or more pages on the screen at once. I want the pages on the screen, one at a time, in order, not side by side. Whoever designed this should be fired.
You could write a feature request that page view should be similar to Adobe Acrobat PDF reader.
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If kindly asked the chance for realization will improve. 
Please take a minute and read this Note about Freeware (especially what it tells about rights, responsibilities and remedy)
There has to be a way get rid of the side by side view. It was the normal view up until recent versions of Libre. I am using 6.1.4.2 and it is the first time I have had this problem.
This is not an answer, use a comment instead.
Your initial description of the problem is rather lacking in clarity and style. But largely by guessing I suspect you have been missing the “One page/Multi-page/Book-view” switches in the lower right corner:
There are three symbols to the left of the zoom sledge. Is this your problem?