How can I recover files from External Hard Drive

I really need some help. This hard drive has years of family photos and important files that I never backed up anywhere else.

I have an old 2 TB external drive. The USB port on the controller board got damaged—looked rusty—and eventually stopped working. So I took the drive out of the enclosure and connected the internal SATA hard drive directly to my PC using SATA cables.

When I checked in File Explorer, it showed the drive as completely free. I’m sure it had over 900GB of data before this happened. I immediately shut down my PC because I didn’t want to mess anything up or risk overwriting anything.

Now I don’t know what to do next. Should I:

Try fixing the original controller board and reconnect the drive as it was?
Connect it again directly and run recovery software?
Or just take it to a data recovery expert and not risk anything further?

What I really want to know is:
Is there still a chance my data is recoverable?
If I reconnect the drive without writing anything to it, is it safe?
What should be my first step?

If anyone’s dealt with something like this before, I’d really appreciate some advice.