obviously, I cannot see the application you are faced with but…
textured wall applications are “great” for hiding joins, the rougher the surface is, the better.
Instead of trying to get bits to stick back down. it is better to just print a “patch”.
Now let’s say you have a rough brick wall and you have stuck the following photo to it.
one side is coming away top to bottom on the right, and the top left corner and a bit in the middle at the monkey’s teeth are all lifting. (highlighted with pink filter).
* Take a sharp scalpel and “cut them out.” so your basically cutting away the parts that are lifting.
* now print patches that are “oversized”.
so if you have a section 100mm x 100mm and it’s coming away.
* make your patch 120mm x 120mm.
* make sure the bad section has been cut away clean.
* make sure the wall is clean as possible.
* do not use spray adhesive etc. make sure that’s also OFF the surface.
* sit the patch in position, heat the vinyl and roll-conform it back into position with whatever you used to apply it.
as I say, the rougher the wall surface the better the patch will be hidden.
the only way you will see it is if the old print is badly faded and the new print is nice and vibrant, even then its a trade-off, for the print being back to its original condition.
before doing any of the above.
Print a small photo and a patch, in your workshop.
stick it to a rough wall, then apply the patch, as above, you will not see it.