Because ppl use Docker, even when it's not really that necessary... I'm using Nix for the past few years and it has obviated the need for Docker. I have simple shell.nix files, which are activated via direnv and that's it; 0 runtime overhead, no need to install various java/node/python/ruby version managers.

What actually feasts on memory is the various chat apps and project management and knowledge-base management software, in-browser email clients, github pages, JetBrains IDEs.

You should keep these closed, whenever u can and then 8GB is enough comfortably. You will still receive Slack notifications on your phone, then u can fire up Slack to reply or have a discussion. Same with Notion or Logseq. You don't need to have a gmail tab open all the time either. The built-in Mail.app might just be enough for you too, which might eat slightly less memory. You can use Sublime Text or Emacs for editing, instead of VS Code or WebStorm. Install a browser-tab suspender extension. Download technical docs and read them via Dash (or whatever open-source equivalent it has). Have you looked into how much memory does a github.com page eats?