Enlarging Photos

I've not used it myself, but there is a Super Zoom tool in Neural filters.  It looks like it zooms in and enhances, so you might need to add canvas before using it.   Otherwise Preserve Details 2 is going to be as good as the third party plugins that are out there.  We had a conversation with Adobe employee Chris Coz about this several years back, and he emphasized that PD2 was as good as anything else.

OK I ran SuperZoom while typing the above, and while it was slow (and I am using a feck-off workstation) the results were definitely good.  Oh wow.  It increased Paddington from 1650 pixels wide to 11,000 pixels wide, and while this might not be the best test subject, the result was spectacular.  Click to expand to see things properly.

Different interpolation methods are best for different purposes.

For example, Automatic is great for downscaling, whereas Preserve Details 2.0 is the most sophisticated for upscaling.