seems similar to the set up for systemd snippets, where you can avoid changing default config files for systemd units and instead use a drop in file in that created .d dir to load and overwrite the defaults on boot for whatever specific thing. don’t know anything that uses this for bashrc, tho. most likely harmless, especially if there’s no created bashrc.d yet.
linux typically won’t hard freeze on errors like that no matter the distro. it can, but rarely. being an all amd build i suspect there’s some cpu bios feature auto scaling core clock or voltage and in my experience ryzen cpus need to have a manually set stable clock and voltage to perform properly no matter the os. try checking your bios and disabling any powersaving or auto-scaling features for your cpu and manually set it for stock clock and voltage. you may need to look up what these values are as the bios might not have a default value for you. this might not be your issue but it’s worth trying. good luck!