Which packages can be removed?

[Scottz]

I'm running nginx and Django/python on Ubuntu 20.04 and would like to remove all unnecessary packages to reduce image size and attack surface and patch frequency.
I assume I can remove apache?
Maybe python2.7?
I saw a thread that it's not good to remove perl.
Is it ok to remove sendmail if only using postfix?
Do you know any commands to list all packages by size, and determine if required?
Thank you

 

[KGIII]

I will tell you this:

Do NOT remove the default Python that came with the system. If you need a newer version, install it beside it. Do NOT remove the default.

The rest of the question we can't really tell you as we don't have your system and know what you need. You can probably remove sendmail if you want. That one seems pretty safe.