Hello Raptor12,
Thanks for posting in the Apple Support Communities.
It sounds like the Screen Time settings are only kept for the day, before being reset the following morning, right?
If we have that correct, let's check that each of the devices in use have the latest available software version installed. If there is an outdated device, see if removing that as an associated device will clear this up as a test for two days. If you see an update is available, be sure to complete a back up before getting started. Take a look at the steps below, and you can find more details here: Update your iPhone or iPad - Apple Support
Update your iPhone or iPad wirelessly
1. Back up your device using iCloud or your computer.
2. Plug your device into power and connect to the internet with Wi-Fi.
3. Go to Settings > General, then tap Software Update.
4. If you see more than one software update option available, choose the one that you want to install.
5. Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do.
If you see that all devices are up-to-date with the latest software version, let's see if we can isolate if this is related to the network connection. While this may take a few minutes, forgetting the network connection to set this up again on each device would be the best step to isolate the home network. Check out the steps below for assistance with forgetting the network, then connect to it again. You can also view these steps, and other devices, here: How to forget a Wi-Fi network on iPhone, iPad, or Mac - Apple Support
Forget a network on iPhone or iPad
To forget the network that you're currently using:
1. Go to Settings > Wi-Fi.
2. Tap the info button next to the network you're using.
3. Tap Forget This Network, then tap Forget to confirm.
We hope this helps to clear up what's occurring. If not, contact Apple Support directly to check into this with you in detail.
Have a great day!