How can I make onboard PC speaker beep on Ubuntu Server 22.04.3 LTS?

I have two old machines that I use as file servers. The first one has a GIGABYTE GA-G41M-Combo (rev. 2.0) with an Intel Core 2 Duo Processor E7400 (3M Cache, 2.80 GHz, 1066 MHz FSB) and the second one an ASRock 4Core1600Twins-P35 with an Intel Core 2 Quad Processor Q9550 (12M Cache, 2.83 GHz, 1333 MHz FSB). Both machines have onboard audio and onboard PC speakers, for sure!!! On both machines I have installed "Ubuntu Server 22.04.3 LTS" and "CasaOS" and I am trying to create a service, or something like that, which will make beep sound using onboard PC speaker (not onboard audio), when CasaOS is loaded. But before I even get there, my problem is when I am testing the "beep" program. On both machines, I can't get the beep sound through the onboard PC speaker.

I installed "beep" by typing sudo apt-get install beep but when I type beep I get this message beep: Error: Could not open any device.

I have read some old similar articles and questions which mention some solutions like sudo modprobe pcspkr, or to comment the blacklist pcspkr line into /etc/modprobe.d/blacklist.conf file, but none of them helped me to solve this issue.

EDIT:

1. When I run sudo modprobe pcspkr it just waits for next input without any errors.
2. The output of running lsmod | grep pcspkr is pcspkr 16384 0.
3. The output of sudo grep -R pcspkr /etc/modprobe.d/ is/etc/modprobe.d/blacklist.conf:# blacklist pcspkr.
4. The output of paplay /usr/share/sounds/freedesktop/stereo/bell.oga is Command 'paplay' not found, but can be installed with: sudo apt install pulseaudio-utils.
5. But I can take a simple beep sound when I run this sudo sh -c "echo -e '\\a'> /dev/console".