Windows 11

Personalization > Background - don't use slideshow or Windows spotlight.

Personalization > Lock screen - don't get fun facts. No one wants fun facts.

Personalization > Taskbar - switch off everything you don't use.

Personalization > Device usage - turn off everything.

Apps > Installed apps - go down every app, select the 3-dot ... menu > Advanced options (where applicable) > set apps to never run in the background if you don't want them to.

Apps > Advanced app settings > Share across devices - turn off if you don't do that.

Apps > Startup - turn off what you don't want starting with Windows. Leave the hardware apps on.

Accounts > Windows backup - turn that stuff off if you don't use it.

Time & language > Typing - go through everything there, turn off what you don't use or want.

Accessibility > Visual effects - always show scrollbars but turn off transparency and animation effects.

Accessibility > Hearing > Captions - turn off if you don't need or want them.

Privacy & security > Windows permissions and App permissions - go through all 32 categories and turn off everything you don't want or need.

Windows Update > Advanced options > Additional options > Delivery Optimization - turn it off.

Press Windows key + R > Open: SystemPropertiesPerformance.exe > Visual Effects tab > set it like this.

Go through each category in Edge settings and turn off the things you don't need or want - if Edge is not your primary browser, turn off 'startup boost' and 'continue running background extensions and apps when Microsoft Edge is closed' in the System and performance section.