apt-get install chromium

2. Start chromium once to be sure it starts and all directories it creates will be created.

chromium

3. Exit chromium

4. Download google Chrome (not chromium) from upstream

https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb

5. Extract the files from the deb-file

dpkg --extract google-chrome-stable_current_amd64.deb .

(this command will extract them into the actual directory, but you can choose any path you like instead).

6. Copy the Widevine directory from the extracted chrome deb-file into the chromium directory where chromium looks for it

cp -r /opt/google/chrome/WidevineCdm /usr/lib/chromium-browser/.

7. Start chromium again and check if netflix will play.

= = =

Note:
I used this setup for years, till the last chromium update break something for me on Devuan 5 Daedalus.
I also started it with firejail, so it was sandboxed:

firejail chromium

On Devuan 5 Daedalus Desktop Live I tested this setup and it was working too.
However, I couldn't fix it on my Daedalus installation, so I made a fresh new install of Devuan 6 Excalibur and it works there too, except with firejail.
I will try to get this to work with firejail too again and then extend this How To.