Wireguard is available in kernel 5.6 or newer, so the question is did you compile kernel 5.6 or newer from the source code and additionally performed update-initramfs after that? And yes this command can show missing firmware which need to be installed. It seems you messed up your system because of wireguard. I am wondering which tutorial did you use to make ...
How to install i915 firmware.
Type in terminal:
sudo mkdir i915
git clone https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git
sudo cp -R linux-firmware/i915/* /lib/firmware/i915/
sudo update-initramfs -u
Type commands in terminal one by one:
tar -xzvf iwlwifi-9000-pu-b0-jf-b0-34.618819.0.tgz
sudo cp iwlwifi-9000-pu-b0-jf-b0-34.ucode /lib/firmware
sudo apt update
sudo apt upgrade
sudo apt install --...
Actually Elementary is based on Ubuntu and Debian, so you are wrong. Install dkms in terminal
sudo apt install dkms
Install deb from 18.04 or 19. 04 using Eddy.
Additionally I am not sure is it a driver for your Realtek, but it works with really old kernel.
I have found this and it looks like this is the Samsung fault. I am not sure, however it seems there is no firmware nor software which could set properly functional keys binding. Unfortunately I am not an expert. Mostly people are complaining about this ...