The Photos App has had the Retouch Tool for a while. I never thought it was good enough to replace Snapheal which is a third-party add-on that I use in Photos. The Retouch Tool is new and improved in the macOS Big Sur version of Photos. If you are not using a third-party App or add-on to retouch your pictures, the Photos Retouch Tool may be all you need. This article describes how to use the Big Sur Retouch Too.