recovery key

A Recovery Key is not automatically generated. If you had created one you would have known about it.

Just to confirm... no Time Machine backup? As you probably figured out by now, Apple's approach to security borders on the maniacal. If you cannot get into your Mac its data is locked away for sure.

A 16 inch MacBook Pro uses hardware encryption which obviates even the need for FileVault's already impenetrable security, so there is no extracting its data, not without its password: Use FileVault to encrypt your Mac startup disk - Apple Support and Encrypt Mac data with FileVault - Apple Support explains how it works. Apple never emphasizes things like WARNING in bold text unless they really mean it. To reemphasize the point, your MBP performs that data encryption in hardware. It cannot be disabled or circumvented so don't offer to pay anyone to try.

I agree the situation such as yours can't be that uncommon and it's unfathomable for it to be hopeless. Give it a rest for 24 hours.

Reset your Mac login password - Apple Support describes all the applicable steps. Most of the options begin with "if" because they may or may not be applicable to your particular circumstances, and you may eventually arrive at If you can’t reset your Mac login password. Follow them too, all the way through, all the way to its conclusion.

I understand. If it is your Apple ID that has become locked, the following may be applicable: If you see an 'Unable to sign you in to your Apple ID' message - Apple Support. A locked Apple ID will cause all sorts of problems, but it might be best to wait at least 24 hours before doing anything drastic like erasing the Mac.

Do you have a Time Machine backup? Having one would mitigate the inconvenience: Back up your files with Time Machine on Mac - Apple Support

You may not have created a Recovery Key, but it might ask for one anyway. Continue with the rest of those Apple Support documents, exhausting each one of its steps, in the sequence provided, including any links they may contain, all the way through to and including the end of each step, all the way to the end, where it states:

"If you still need help, please contact Apple Support."

Thoughts on Recovery Key as it relates to FileVault and if you elaborate to the OP this maybe also a Factor 🤞

I understand it could be a factor, but if that Recovery Key is lost or unknown it's not an option anyway.

Agreed 👍