A required firmware update could not be installed. Compatible internal storage is required in order to update

Is this the original Apple SATA SSD which shipped with this laptop from the factory? Or did you acquire an Apple OEM NVMe SSD from another Mac? If the latter, then macOS knows the SSD is not original to the laptop and macOS may not work correctly with it.

Unfortunately the screenshots don't mention the type of SSD such as "SATA" or "NVMExpress". Click on "SATA" and "NVMExpress" on the left pane of the System Profiler to determine if this is a SATA based or NVMe based SSD. The original Apple SSD which shipped with a 2015 laptop was only a SATA based SSD since Apple did not include the necessary system firmware or NVMe driver into macOS until macOS 10.13+.

Thank you very much for images above.

Yes this machine does Qualify for Monterey but just qualifies

May I suggest two possibilities for a possible solution.

Remove any application called Install Monterey appearing in the applications folder - if one exists.

The empty the Trash

Download the Full Version of Monterey ( about 12.xx GB ) in size

Do this from Terminal using the below command

You may what to copy and past the command for better results vs re-typing it

softwareupdate --fetch-full-installer --full-installer-version 12.6.3

The press the Return key

This will Only Download the Full Version and Will Not Launch it

Once is appears in Application folder I would Stop there.

Restart in Safe Mode. just to insure nothing else is running

Now launch the Application like any other application.

Finger Crossed 👍 the EFI BOOT ROM contained in the Full Version will Flash the Computer ( not drive ) and a successful installation will occur

Welcome but it does not solve the computer issue 😂

Have seen, only in passing, some other uses with this type of issue and never paid too much attention

Working Remotely as we are from around the world 🇨🇦 here.

The best I can suggest at this point >>

Then have a few suggestions ;

1 - Get Support Choose a product and we’ll find you the best solution.Start now and open an Apple Support Ticket as they are Apple Employees to deal will these types of issues . 

2 - Have the computer evaluated by the Professionals who have the Special Hardware Software and Expertise to diagnose the issue and offer possible solutions

If going this route, would be genuinely interested in the out come.

Welcome but and yes a but a " Hail Mary " 1 second on the clock

If you wish to explore the Apple Trade-In  Process where the Value of the exiting device could be used against the cost of a new Apple Computer, iPhone or iPad  

Or Shop Refurbished Apple computers at an Apple Reduced Cost

Have used both previously and have been satisfied each time.

How about giving us a Screen Shot from " System Information >> Storage ".

That will give us a much more clear understanding of Apple Original Drive vs After Market Drive

refer to image below