Can't Use YubiKey 5 Nano for Smallstep Tiny CA on RPi4B

[AlexLandherr]

• YubiKey Manager (ykman) version: YubiKey Manager (ykman) version: 4.0.7
• How was it installed?: sudo apt install -y yubikey-manager
• Operating system and version: Downloaded via this direct download link.
• YubiKey model and version:

pi@tinyca:~$ sudo ykman info
WARNING: PC/SC not available. Smart card protocols will not function.
Device type: YubiKey 5 Nano
Serial number: 13833527
Firmware version: 5.4.3
Form factor: Nano (USB-A)
Enabled USB interfaces: OTP, FIDO, CCID

Applications
FIDO2 Enabled
OTP Enabled
FIDO U2F Enabled
OATH Enabled
YubiHSM Auth Enabled
OpenPGP Enabled
PIV Enabled

• Bug description summary:
  Can't execute this command ykman piv certificates import 9a /mnt/ca/certs/root_ca.crt from this tutorial.

Steps to reproduce

See this other discussion's OP for details.

Expected result

To be able to execute this command ykman piv certificates import 9a /mnt/ca/certs/root_ca.crt without issue.