iPad 5th gen suddenly dead

I have a 5th gen iPad that I bought certified refurbished from the Apple store in 2020. The iPad's battery has been draining a little faster than usual over the last few months, but otherwise the iPad had no issues.

After updating the OS to 15.3.1. the other day and taking the iPad off its charger when it reached 100% charge, the iPad died and will not power on. There is no response whatsoever to being plugged back in or a forced restart.

Since the battery had been showing evidence of decline, I assumed it abruptly failed. I believe this iPad is still worth the money to replace the battery at $99, so I started an Apple mail repair order.

When choosing the issue to be repaired, I chose "will not power on" (since it won't). The next screen presented me with an estimate of $249 to repair the unit.

My question is: If it turns out that all the pad needs is a battery, will they only charge me the $99? And if it's not, do I have the option of declining the $249 "estimate" once the actual problem has been diagnosed?

Thanks for the help.