[Quoth]

Use a proper scanner. An archival scanner allows the book to sit thus \/ and uses far better cameras and lenses than in any phone. If it's a common book and the scanner has an ADF, the spine is usually cut off. An expert copy typist (maybe none left?) can probably beat an inexperienced person with a camera phone and need much less proof reading/editing.

Do make sure the copyright has expired. That is now quite complicated.

You'll want to proof read it entirely several times, with a gap of at least a week. You'll not see most of the errors if you are not experienced at proofing.

Pirates do this with ARCs and simply upload a PDF with unproofed text for search to Google Books/Playstore. IMO, the piracy on that and also pirated books packaged as Apps on the Playstore, that Google's book sales/distribution and their scanning of books for search (they DO store entire copyright works on public servers, they mislead during the court case).