Unable to install OS to a new SSD on mid-2012 MBP

Purchased a set of 2x8 GB DDR3 RAM sticks and a new SSD to breathe some life into an old mid-2012 Macbook Pro.

The RAM seems to work well, but I'm struggling with replacing the existing HDD with the empty SSD. Tried the following:

1. Building a bootable USB with OpenCore Legacy Patcher - FAILED - the installation fails at the end with a message that was something like "An error occurred loading the update", ends with a flashing folder after reboot.
2. Swapping in the SSD and booting through Internet Recovery - FAILED - it fails at the end with a message similar to #1
3. Cloning the HDD to the SSD using Carbon Copy Cloner - FAILED - the clone gets copied successfully, but when I put in the SSD, I get a flashing folder.

https://preview.redd.it/tbbzedzf49xc1.png?width=764&format=png&auto=webp&s=ce79b24ba0b7406fe5adf3f191ce61fb21ec3fb3

Some people have mentioned a bad SATA cable, but I don't think that's the case because when I swap back my old HDD in the Mac, it boots up to desktop reliably.

TL;DR: I have absolutely no idea how to get the SSD up and running in the Mac, and all attempts have failed.

Any tips or other avenues to fix this?