Google Play Store relies heavily on Google Play Services. If you are installing on a device without Google services (like a custom ROM or a Chinese phone), you need to install Google Play Services first.

You want to access new user interface designs or features before they roll out to your specific region.

Go to Settings > Apps > Google Play Store , tap the three dots in the corner, and select "Uninstall updates". Then, try installing the new APK again.

Rooted users or aggressive debloated software can sometimes accidentally remove or break core system apps.

System updates or rooting processes can sometimes break or remove core Google apps.

On rooted devices, the Play Store can sometimes be accidentally removed.

You downloaded an APK meant for a different processor type (e.g., 64-bit instead of 32-bit). Look for a "universal" variant on the download page.

Why someone wants the APK