Interpolation is available on cell phones. I use interpolation iphone app, Hydra. There are cameras with the options.
INTERPOLATION DEFINED Google search click here.
Photograph with a Windows phone with 41 mp.
Or stitching the images also works well but you have to past one image over another. This requires moving the camera tripod or turning it. There is also layering the images post shot. I use the HDR effect/option from NCH software PhotoPad professional license.
Or Pixlr.com online editor.then repaint with Windows 3D or FireAlpaca software. I use these to the most. I love the way I can spread images like this with FireAlpaca.
I have often wondered about high definition flatbed scanners. When I searched online I found many scanners from 2000mp up to 6400 mp, mega pixels, from the $100 up to $900.
When I watercolor or paint a smaller canvas, I could easily us a flatbed scanner to enlarge my photographs.
Editing on the cell phone.
I use Editor from MacGyver an Android app I use to enlarge only digital photos I manipulate. Fossil defused effect.
Honey Rose an enlarged watercolor with varying layers and effects.
For a paint effect after enlargement, try painting effect #7 brush strokes from Fotosketcher. https://fotosketcher.com/
I hope this helps. Have a great day.
Art Group Admin.