Hello, and thanks for the response.
Regarding the hardware I can confirm the computer has an amd64 cpu. In
any case, I also tried installing the i386 port and the result is
exactly the same (except for the default font size of the terminal).
Regarding the origin of the binaries, I've been using the official USB
images from the 11.1 release in the NetBSD main page. When prompted to
choose a source for the kernel and distribution sets, I've tried both
installing from the install media and from the official CDN via HTTP,
and still the same. Just in case I've also tried the 10.2 release, but
no luck.
Any suggestions?