I use bun for everything except for monorepos with isolated deployment targets and shared packages. I use yarn or pnpm for monorepos. Maybe it's changed in the last six months but I could never get docker to properly resolve my dependencies when I only want to build the web app, for example, since the bun lock is deterministic based off of all the packages in the repo so isolating a single leaf makes it error.
Maybe I'm doing something wrong but I scoured docs and online and asked multiple AI agents to no avail.