Cannot sign into Apple ID on iMessage iPad

I couldn’t find anything that worked when I was looking up my problem so I thought I’d ask here. I’ve been using an iPad for about 2 years. My son found an iPad in his room (I don’t know how it got in there!) that hasn’t been used since around 2018. To make this easier to understand, the iPad that I’ve been using is iPad A and the iPad my son found is iPad B. iPad A is cracked so I started using iPad B again. Earlier today I went to the messages app to text and it told me to Sign In with Apple ID. The problem is that I can’t even click the sign-in box at all, there’s no touch response. I tried to go to messages in settings but messages, FaceTime, and even my Apple ID are grayed-out and I am unable to view the settings for them. My iPad is connected to WiFi. I don’t know if this is an Apple ID issue, or if something else is wrong.

TL;DR:

I can’t sign into iMessage on my iPad because I can’t click the box to type. iMessage, FaceTime, and Apple ID are grayed-out in settings and I can’t view those either.