Looks great, well done.
Personally, the deb-related annoyance that I have encountered most often in recent years is that there is an APT repo but I have to jump thru hoops to add it. An example is signal-desktop, where the handy one-click installation goes like this:
# 1. Install our official public software signing key:
wget -O- https://updates.signal.org/desktop/apt/keys.asc | gpg --dearmor > signal-desktop-keyring.gpg
cat signal-desktop-keyring.gpg | sudo tee /usr/share/keyrings/signal-desktop-keyring.gpg > /dev/null
# 2. Add our repository to your list of repositories:
echo 'deb [arch=amd64 signed-by=/usr/share/keyrings/signal-desktop-keyring.gpg] https://updates.signal.org/desktop/apt xenial main' |\
sudo tee /etc/apt/sources.list.d/signal-xenial.list
# 3. Update your package database and install Signal:
sudo apt update && sudo apt install signal-desktop
Why does Debian-Ubuntu not provide a simple command for this? Yes there is add-apt-repository but for some reason it doesn't deal with keys. I've had to deal with this PITA on multiple occasions, what's up with this?