Hi, and welcome to the community.
Unsure if you mean something else, but look at each apps settings and turn off any auto start feature. Personally, I've never seen this behaviour.
If you mean Auto play videos, then...
If Google Play Store, then see 1st screenshot
If Galaxy Store, then see 2nd screenshot.
I can't see any other settings in either Google Play store or Galaxy store that mentions auto start of apps.
