Whatsapp back-up went wrong with broken phone

Hi - this is a bit confusing to explain, and I may not have done a very good job.

I was on holiday for a period of a few months, and during this holiday, my Samsung phone stopped working. It would still turn on but the screen just stopped working. I urgently needed a new phone so I could continue to text people and use Whatsapp and the Internet and my various tickets/itineraries so I went and bought a Huawei phone.

My problem was that my phone had stopped making cloud backups (I must have accidentally turned this off). SD card back-ups were still happening but the SD card would not eject. I could not get the damned thing out. The technician at the store I bought the phone at also had no luck and suggested I go to a Samsung store to do it (and I didn't have time as I was due on a plane that evening), but I wasn't close to one of those. Also, tragically, USB Debugging was not on on my Samsung phone. So I had to install Whatsapp fresh with no backup.

I did later get the SD card extracted and backed up so I have a .crypt12 file from the old phone. How might I go about seeing some of these messages? I have the same number on the new phone that's using Whatsapp and I was wondering if the encryption key used on the new phone would also unlock the .crypt12 that I have copied from the SD card in the old phone as it's the same number/account etc etc.

I'm thinking I might just have to take the whole phone to a Samsung place and ask if they can replace the screen temporarily and see if they can copy some stuff then put the broken screen back on, which might be cheaper than them paying several hundred dollars to replace the screen. A mobile place near the last stop on my trip offered to do this but they wouldn't have got the part in time.

Or am I going to be out of luck here?