Airbag light turn on and the speedometer stopped working?

Hmm, that's a good one, I would start by checking all fuse with the key on, this guide can help:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

If the fuses are okay, let's do a CAN scan. You can get a CAN scanner (Controller Area Network) which will work on most cars from Amazon.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

To me it sounds like the instrument cluster has gone out or you have corrosion at the cluster's electrical connector. You might want to remove the cluster for inspection. I have marked some fuses I would make sure are getting power. Also, how to remove the cluster as well. Check out the images (below). Let us know what you find.