AFAIK Calm and Insight don't have hundreds of millions of users nor is the CCP on their corporate boards. But with explanations provided by the apps as to why they want network device access they probably
shouldn't be trusted.
As for the data collection, TikTok/ByteDance is definitely going to store it. They wouldn't collect it otherwise. To the utility of the data, if they've got MAC addresses of devices on your home network they can tell many of the brands of devices you own. They know when you get a new computer even if you never use TikTok on it. If you launch the app at your office they get the same information about your office network. In aggregate their network scanning will collect vast amounts of data.
The TikTok app is turning every user into a passive network scanner. Even if you want to ignore the CCP's influence on ByteDance I don't think there is any reason to give them the benefit of the doubt about their data collection. They'll sell their users and anyone around them. I have the same problem with Facebook and their damn shadow profiles and covert data collection.