There’s no way to do it in the smartthings app, but what many people do is hide these type of switches in a “room“ which is only used for devices that you don’t want people to activate through the app. That will work for many people, but not all.
The other alternative is to use one of the third-party dashboards like action tiles or sharp tools. With these, you can build a custom dashboard for each person so they only see the devices you want them to see. This is popular, for example, for people with school-age children where they don’t want one child turning off the lights in the other child’s room.
For more about these options, see the following discussion thread. (Although the topic title mentions wall panels, these dashboards will all run in a web browser, so they will also work on a phone.)
FAQ: Sharptools , actiontiles or native ST app for your wall panel? (2020)
Note that one of the contributors to that thread, @tgauchat , Who was one of the action tiles developers, sadly passed away a few months ago. If you have any questions about one of his posts, just tag @625alex and he should be able to answer you there.