I have a 72-DPI PNG image residing on Monterey 12.0.1:

I can select the first cell of the image scaled at 100% by triple-clicking the text, and copy/paste that into Pages v11.2 on Monterey 12.0.1, arriving in the default Pages font and text size. Note that the Live Text result when pasted into Pages (or LibreOffice Writer 7.2.2) does not conform to the original image text, as the first v is promoted to upper-case, so be prepared to verify the result:

However, I cannot select the text from a PDF whose content was scanned by VueScan Professional v9.7.67 on Monterey 12.0.1. Unless I missed something, the Live Text page from my previous Preview User Guide link did not mention its capability with PDF documents.