How to install Dropbox without apt-key?

Apparently apt-key is deprecated because its design contains a security risk.

The solution is to download the key and store it in a location writable only by the root and then to manually create a sources.list entry with the signed-by option.

For example, to install chrome we can do:

sudo wget -O- https://dl.google.com/linux/linux_signing_key.pub \
    | gpg --dearmor \
    | sudo tee /usr/share/keyrings/google-chrome.gpg >> /dev/null
echo deb [arch=amd64 signed-by=/usr/share/keyrings/google-chrome.gpg] \
    http://dl.google.com/linux/chrome/deb/ stable main \
    | sudo tee /etc/apt/sources.list.d/google-chrome.list >> /dev/null
sudo apt update
sudo apt install google-chrome-stable -y

The problem with this solution is that I cannot find the Dropbox signing key.

Dropbox help centre mentions a key for Fedora, but not Ubuntu:

https://linux.dropbox.com/fedora/rpm-public-key.asc

It all seems quite complicated. Are there some fool-proof, safe, non-deprecated ways to install Dropbox?