Need some help with questions about a sub/amp combo i got

So it claims to be a 10 inch 1200 watt sub/amp underseat combo, and I'm wondering if it'd be possible to wire in a second sub or tweeter, would this be possible?

Would it be louder?

Is there a chance if damaging something?

I got it from temu (i know) but it seems like the same one is on Amazon for $150 and i got it for $68 on a $15 off coupon. And it comes with the wiring.

I'm glad i didn't go for my original option of a wedge boxi saw on Facebook for the same price, because i honestly don't know where I'd put it in my Corolla hatchback since i use my cargo space all the time