I agree that using browser-based password managers is not a good idea, but everything else you said was willfully ignorant.

• OneNote isn’t that special, and you don’t need Windows to use it.
• There are half a dozen excel competitors that are feature complete (OpenOffice, LibreOffice, GSuite, Zoho, Gnumeric…)
• All shells use the same standard tools, excepting a few bulit-ins (because most tools are external to the shell). Some shells have different syntax, but most of them share most syntax. In 90% of cases, the default shell is bash, or an offshoot (dash, etc), which are all descendants of sh, so unless you’re using an extended feature set, scripts are cross-compatible.