Hey Frostyys,
If you haven't already, clean your AirPods and charging case as dirt and debris can cause connection and charging issues. Be sure to check around the buttons too for any build-up as you mention the setup button doesn't seem to work any longer. Here's a wonderful guide on cleaning, just in case: How to clean your AirPods, AirPods Pro, AirPods Max, and EarPods - Apple Support
After cleaning them, see if the case then charges as expected. If needed, try while using a different cable: If your AirPods won’t charge - Apple Support
If the behavior continues, try resetting them once more using these steps: How to reset your AirPods and AirPods Pro - Apple Support
1. Put your AirPods in their charging case, and close the lid.
2. Wait 30 seconds.
3. Open the lid of your charging case.
4. With your AirPods in your ears and connected to your iPhone, iPad, or iPod touch, go to Settings > Bluetooth, or Settings > [your AirPods], and tap the More Info button
next to your AirPods. If you don't see your AirPods in Settings > Bluetooth or in Settings > [your AirPods], just go to the next step.
5. Tap Forget This Device, and tap again to confirm.
6. With the lid open, press and hold the setup button on the back of the case for about 15 seconds, until the status light on the front of the case flashes amber, then white.*

7. Reconnect your AirPods: With your AirPods in their charging case and the lid open, place your AirPods close to your iPhone, iPad, or iPod touch. Follow the steps on your device's screen.
Keep us posted on the results.
Take care!