Is using AppValley to download free apps safe and warranty-compliant on Apple devices?

Things to consider:

• The website says the free version is currently revoked. Use of any downloaded app would be subject to be revoked at any time and you would no longer be able to use it.
• You have to pay $8.99 a month where they claim an app will not be revoked while paying, but acknowledge that it can still happen even if you pay. That is not free. You can subscribe to Apple Arcade for $6.99 a month and have no limits.
• The most worrisome problem is you have to install a Developer Certificate on your device that lowers your security and allows a third party to access your device and the data on it.
• It would not void your warranty, but your device could certainly be compromised and require it to be wiped where you would lose all your data and not be able to restore from a backup.

Third-party App Store apps reportedly using third-party enterprise certificates in unauthorized ways to override device trust settings and to load who-knows-whether-hacked apps are not something I’d want to install on my devices with my data.

As for any questions about how Apple might interpret this and might react, you’ll have to ask them.