Preview: Zoom slider or buttons, option fix size

I wish :
1. there was a zoom slider/were zoom buttons, or nnn%, in the preview top bar, where it says "Open" "Open Folder"..etc.
2. the size can be fixed

Each time I need to click on context menu->Zoom->Zoom Out, and again on context menu->Zoom->Zoom Out, to get the preview the way *I* want.
Also, as an example, if I have a PDF preview and scroll out, and then browse to the next page of the same PDF, the next page is again displayed way too large, i.e. the size of 'zoomed out-preview' of the first page is not maintained.

BTW, one should be using ctrl-scrollwheel in an attempt to use that as a zoom hotkey combination...
The entire preview is gone then.
Oh ... and ctrl- +/- or alt- +/- or ctrl+alt- +/- doesn't help either.

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