Three edits, no re-encoding
Rotation is written into the page, so the file opens the right way up in every reader, not just the one you fixed it in. Deleting pages is often the quickest way to shrink a PDF. Reordering copies pages into a new sequence. None of the three touches the text or the images.
What you lose
The operation underneath copies pages, not the document. Bookmarks do not survive, because the outline points at the original page objects and those references do not come along. Form fields may stop behaving as fields. Digital signatures break, as they should: a signature covers a specific arrangement of pages, and you have just changed it.
A password-protected PDF cannot be opened at all. The tool says so rather than pretending. Remove the protection in whatever applied it first.
If any of that matters, keep your original. This writes a new file and never overwrites what you dropped in.
Deleting beats compressing
People reach for a compressor when a PDF is too big for an upload form. For a scanned document that often does very little, because re-saving a PDF rewrites its structure and does not re-compress the images inside it. A scan is a stack of photographs, and the photographs are the size.
Removing the pages you do not need cuts the file roughly in proportion, immediately. If you need every page but still need it smaller, split it into parts and send them separately, or rescan at a lower setting. If the pages began as photos, compress the images before building the PDF.