Password not working in recovery mode

What OS is booting when you try to boot normally?

I would recommend installing macOS to an external USB3 drive, then boot from the external drive. This may allow you to either migrate everything from the internal drive, or at least manually transfer your files to external media. Just make sure to use Disk Utility to erase the whole physical external drive as GUID partition and APFS (top option). Within Disk Utility you will need to click "View" and select "Show All Devices" before the physical drives appear on the left pane of Disk Utility. Erasing a drive will destroy all data on that drive.

If you have another Mac running macOS 10.13+, then you could try putting the 2015 Mac into Target Disk Mode so that it will appear as an external drive on your other Mac. It would be easiest if the other Mac is running macOS 12.x+ due to the multiple APFS volumes utilized by macOS 11.x+, but you can still use older versions starting at 10.13 with a little more work. You will need to connect the two Macs using a Thunderbolt cable since your 2015 Mac now has Monterey on it.

Another option would be to remove the SSD if it is a MBPro and install it into an OWC Envoy Pro Enclosure so you can connect it to another Mac running macOS 10.13+. This enclosure is a bit expensive, but there really are not many options since Apple uses a proprietary SSD connector with their SSDs.

Is Filevault enabled on this 2015 Mac? If so, then you will either need the correct password, or reset the password, or use the Filevault Recovery Key to unlock the drive. Resetting the password would require the SSD to remain installed in the Mac.

I am not as hip on the versions and the proprietary issues. I tend to power through thinking hardware is hardware. You will need an additional drive I suggest trying to boot for a fault-free drive and then peering over to your problem drive to see what you can migrate to the fault-free drive. You seem to have a drive with issues there 2015 is 8 years regardless of pristine conditions or not. The issue I would think would be a priority would be to recover the data you have if you can then try to recover the machine configuration as an Apple device. Once the data is less of a concern you can be more experimental with researching the solution. I had backups and it was still a pain to recover my device once M2.SSD has problems. I had to go back to dumb hardware and then rebuild from there. You will need your Apple ID to be clearly reliable though at some point to move forward. Take one issue at a time. Work slowly and diligently solving one issue at a time. I'm not sure how technically helpful this is but process is just as important as technical knowledge. I have been on computers of all sorts for close to 40 years now. They are dumb and stubborn but they do not have emotions. ;-) OG/OS