Based on your comments, my first assumption is that the battery is dead. You could try leaving it plugged in to a 2A Apple charge overnight, possibly even for a day to see if it manages to charge the battery. If it does, check the battery condition with a software tool like 3uTools or the iOS Battery Health Diagnostic (not sure if it’s available on the mini 2). If the battery is less than 80% design capacity, then it needs to be replaced.
Even if the overnight charging doesn’t work, I would still suspect the battery. The one thing you didn’t mention is wether or not the iPad worked after it was smashed but before it was left in a drawer. Yes, a hard physical impact could cause some logic board damage but regardless, the first thing to try is a new battery.