We use Photoshop as an adjunct to Lightroom Classic for any complex multi-image or multi-layer image editing.

Photoshop has a steep learning curve as it is very powerful with huge scope, but there are plenty of tutorials to be found online that make it easy to learn whatever techniques you need.

Photoshop is part of the Adobe Creative Suite pitched for photographers as a cut-down part of the Creative Cloud offering aand can be downloaded from the Adobe website.