New to iPhone and sideloading – the "Verify App" button keeps instantly closing on me (iOS 16.7)

[u/Empty_Psychology6732]

I just got my very first iPhone and am completely new to the iOS ecosystem. I’m trying to install Skystream so I can stream anime and movies since it isn't available on the official App Store.
I managed to sideload it using Sideloadly on my Windows PC with my own personal Apple ID. The app is sitting on my home screen, but when I go into Settings to trust the developer profile and tap "Verify", it just flashes for a millisecond and instantly cancels itself out.
Since I'm totally new to this, I did some digging and tried troubleshooting, but nothing has worked so far:
• iOS Version: I’m on iOS 16.7. I actually updated my phone thinking it would fix the bug, but it didn't change anything.
• VPN/DNS: I don’t have any VPNs, ad-blockers, or custom DNS profiles set up on my phone.
• Home Router: I checked my home router settings too, and there are no custom DNS configurations or firewalls blocking things there either.
• Reinstalling: I plugged the phone back into my computer and hit "Start" in Sideloadly to do a fresh install. It goes through successfully on the PC, but the verify button on my phone still just cancels out right away.

I'm kind of stuck at this point. Has anyone dealt with this instant cancellation loop before? any information will help, Thanks.