The Legion 5P-15ARH05H has an MSFT0001:00 06CB:7F28 touchpad which was not responding to input. A fix is mentioned in this linux.org thread It entails enabling pooling on the device. This is achievable by creating the following two files in ~/Documents,

fix_trackpad.service with the following content,

[Unit]
Description=Fix the trackpad on the Legion 5P
 
[Service]
ExecStart=/usr/bin/fix_trackpad.sh
 
[Install]
WantedBy=multi-user.target

And fix_trackpad.sh with the following content,

#!/bin/sh
echo 386 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio386/direction

Then, issuing the following instructions once to set up the fix to be applied after every reboot or cold start,

$ sudo cp ~/Documents/fix_trackpad.sh /usr/bin/
$ sudo cp ~/Documents/fix_trackpad.service /etc/systemd/system/
$ sudo systemctl enable fix_trackpad

Yet, additional reading showed pooling is not the best solution for this.

The recommended fix, discussed in bug #1887190, is based on interrupts instead of polling. Interrupts are better than polling for power management.
How do we fix this? comment #189 contains code which is a stand-alone version of the solution in comment #171.
This stand-alone version is only useful if the module pinctrl-amd is built out of the kernel. To check if that is the case, we must execute,

$ modinfo pinctrl-amd

For arch-based distributions this is the case so the stand-alone solution works. Based on these findings, we must compile and install the module.
The instructions to do so are available on the same comment #189 linked earlier.