folders within container folder

If you are referring to deleting folders within the container folders (located in ~/Library/Containers) then doing so can not only be risky, but is generally not recommended unless you know exactly what you're doing. These container folders are part of macOS's application sandboxing framework and store data, preferences, caches, and other app-specific files.

I can only think of three situations that you may want to do this:

• You are performing app-specific troubleshooting. If an app is misbehaving, deleting its container folder may reset its data and preferences, effectively giving it a fresh start. However, this will result in the loss of any app-specific data stored locally.
• You want to perform some cache cleanup. Some of these container folders may only store cache or temporary files, which should be safe to delete. However, remember that macOS handles cache management automatically, so manual deletion is rarely necessary.
• You uninstalled an app and want to make sure you remove any traces of it. Some of those traces could reside in a container folder.