Apple Watch Erase all Content and Settings Loop

I'm experiencing an issue with my Apple Watch Series 1 (38mm). Every time I turn it on, I get a prompt with two options: "Erase all content and settings" and "Cancel."

When I select "Erase all content and settings," a progress ring appears, but just before it completes, the watch restarts and shows the same prompt again, creating an endless loop. If I choose "Cancel," nothing changes—the prompt still reappears, and the cycle continues.

Additional details:

• The watch only turns on when connected to the charger.
• The side button is not working.
• Pressing the crown without the charger only shows the Apple logo for a second before shutting off.
• When clicking "Erase all content and settings," the watch must be plugged in, or else it shuts off after showing the progress ring.

Does this suggest a faulty battery? I’m a student, so replacing the battery is my only budget-friendly option. I can’t afford to upgrade.

Has anyone faced this issue before? How did you fix it? Any help would be appreciated!