Have you tried checking if the apps are up to date? If you're unsure, please head into Play Store > Search the apps you're experiencing issues with > Update (if there's an update available).
Hmm, that is quite strange. As the issue only occurs when using Wi-Fi, it does sound like it's solely linked to this. You also stated it occurs with a select few apps, and not all. So, have you tried reaching out to the app developers regarding this?
You won't be able to change the connection on the phone when using Wi-Fi, as this option is only available when using Hotspot. But, it's still quite strange. Are there any other Samsung's being used in your home? Have you tried connecting to another Wi-Fi connection when out?