Screen displaying, but touch dose not work.

Although it wouldn't hurt to check the connector, you're almost certainly looking at needing to replace the screen. It's unlikely to be something as simple as a connector that's come loose, as the display connector on your phone is held down with a metal plate and a screw, so they virtually never come loose even as a result of a fall.

Even though you don't see any visible sign of damage, there are delicate connections between the flex cable and the glass that the digitizer circuits are printed on, and a sharp shock such as a fall can easily be enough to disrupt those connections. Unfortunately, once they've broken loose they can't be reconnected so the only solution is to replace the screen.

Here's the guide you'll need to do the job; if you want to support iFixit's repair efforts you can buy the screen right here on this website, but if you're more cost conscious you can easily find them on sites like Amazon, eBay and AliExpress.

Google Pixel 7a Screen Replacement - iFixit Repair Guide

That should be everything you need to get your phone working again; good luck with it and be sure to come on back and let us know how it all turns out!