ChatGPT Projects: give each workstream its own instructions and memory
Project instructions override your global custom instructions inside that project, and project-only memory keeps context from leaking across.
Productivity tips
Customize Audio Overviews: Brief, Critique or Debate instead of the default
Google's notebook tool (formerly NotebookLM) can turn your sources into a 2-minute brief, a critique of your draft, or a debate, plus a custom focus prompt.