"InstallAssistant" generated a memory access violation (segmentation fault in which the process tried to access memory outside of its allocated memory segment).
Couple of suggestions:
- Use a good name brand USB flash disk (USB 3.0 preferred) and capacity of 16GB or larger.
- Erase the USB flash disk.
- Re-create the USB flash disk (no need to re-download Catalina...yet) by following the appropriate sections of Step 2.
- Try the installation again using the new or reformatted USB flash disk.
Do you have another SSD available just in case there's a problem with WD M.2? Even a SATA SSD can be used temporarily.