Microsoft Word closing whenever I navigate away to other apps. Macbook user.

i’d expect this if your Mac is badly memory-constrained, but not otherwise. How much memory and swap usage is showing in Activity Monitor app?

As an alternative, you can read and write most Office documents with LibreOffice, or Pages, Keynote, or Numbers.

Or you can take steps to reduce memory usage, including removing “coffee shop” VPN apps, add-on security apps, add-on cleaner apps, and similar.

Here’s the Microsoft 365 support forum: https://techcommunity.microsoft.com/category/microsoft365

That’s the processor display, not the memory display.

However… Remove the cleaner app.

Remove all add-on cleaner apps, all add-on “coffee shop” VPN apps, all add-on security apps, all add-on firewall apps, all removed per the vendors’ instructions, restart, and test again.