My article was recently published on Linode on how to setup many WordPress websites on a single server, and put each website inside LXD containers. By doing so, you can have greater density on your VPS and more value for money.
Apart from that, it also has great educational value to go through all the process and doing the setup manually. By doing it manually, it would be easier for you to graduate and move to using orchestration software.
The article was in the queue for publishing for quite a bit of time and it shows because it mentions Ubuntu 18.04. But still it works great and should be lighter than Ubuntu 20.04.
Here is the article,