endless "verification required" loop when trying to download apps

After trying to download a free app, I get greeted with a "Verification Required" popup that asks me to fill in my payment method. I fill it out, tap next, and the popup goes away - only to come back again. I did this a few times before giving up because it was going nowhere. From what I understand it's because I have "pending purchases" in my purchase history, but I'm unable to find out how to have them go through and stop pending.

I searched the internet about this and I did every instruction I could find.

• Removed previous card details.
• Attempted to re-input card details, but it was declined.
• Restarted my phone.
• Logged out of my AppleID, logged back in.
• Updated software to iOS 14.0.1.

If I'm just an idiot and there's a really easy solution I would LOVE to hear it. Any help?