Cannot enter password in recovery mode to mount Internal HD (or reinstall OS)

It's definitely weird that the drive shows up, but doesn't let you type in the password. I'm sorry to say that this sounds like a hardware problem and will need a physical solution (...assuming of course, the techs that actually reviewed the device when you took it to them echo that sentiment...if they said anything otherwise, I'd love to hear it).

The drive is being seen, so that's a good sign; it just can't use the macOS that is on there (which is more of a loaded statement than it sounds). There are data recovery services that you can look in to, if the data is worth the cash. If it's any consolation, I've heard miracle stories of some of them being able to recover data even after the drive itself has been mauled and/or burned. YMMV but, considering all that you've done so far, I think thats' the best move to make at this point if you want to save that data.

Best of luck mate

I have personally used Drive Savers several times in the many years ago and was very satisfied with them. Both Drive Savers and Kroll Ontrack are the two main companies that most major OEMs recommend to users and both provide free estimates.

Not sure if it's worth anything, but the only time I have been able to locate my user is when I use the terminal>reset password call.

...👀...

I feel like that's not supposed to even get you that far, considering what's happening. (I know, that's not a helpful statement in the slightest...but at least you have someone backing you up when we say - that's weird) lol

Do you have any others you would suggest?

DriveSavers is the only one I've heard of outside of simple searches on the internet.

Some other ones I've seen talked about are CBL and Lazarus. Of course, that is also going to depend on which part of the globe you are. I'd also recommend looking around your locale to see if someone offers the services there; may still not be cheap, but it's always good to have options.

Best of luck dude