Hi Amanda
Welcome to Microsoft Community.
Based on your description, I understand that you removed Roblox from your restricted list, but your daughter is unable to find the Roblox app in the Google Play store, and I understand exactly how you feel!
I will give you some options to hopefully resolve your issue successfully! However, the first reply may not be able to solve your problem successfully due to the different aspects of troubleshooting required for this issue, so please understand and provide more information (pictures would be better!) in your reply. Thank you very much!
Option 1: We try to clear the cache and data for your daughter's cell phone.
Below is a sample procedure:
Open Settings -> Apps -> Google Play Store -> Storage
Clear cache and data, this step will help us to refresh the list of apps in the store.
Option 2: We will try to search for Roblox in the browser and go to the official website and click on the download link in the official website.
This will either download the Roblox .apk installer or redirect you to the corresponding app download page.
Option 3: Ensure that her device is compatible with the Roblox application. If the device is old or has limited storage space, it may not be able to display the app in the Play Store.
Option 4: We can consider temporarily uninstalling the Home Security app from the phone and reinstalling it again, sometimes the problem can be caused by permission changes that don't take effect after a refresh.
In addition, considering that you may encounter some troubles when you operate it by yourself, and that the family group contains some personal information (PII) of you, your family members and your children, in order to prevent your privacy from being leaked in public, or even from being misappropriated!
I will also provide you with a way to contact telephone support and online support.
Please contact Contact Us - Microsoft Support for problem related help and support, thank you very much!
(1) Click on the link to visit the website and sign in to your account
(2) Enter the problem you are experiencing in the search field.
Below are some example images:
(3) Click on “Get Help”.
(4) Click on “Contact Support”.
(5) You can check for help, or seek online and telephone support.
Tips: I personally recommend that you contact online support or phone support, they have remote assistance access and can help you remotely to check your homegroup settings or help you resolve the issue.
I sincerely hope that the above solution will solve your problem. Please feel free to contact me if you have any problems or still can't solve them. (Photos related to the question would be great!).
I look forward to hearing back from you.
Best Regards
Arthur Sheng | Microsoft Community Support Specialist