If you're on Windows 10, this may help:
https://www.tenforums.com/tutorials/76759-restore-default-themes-windows-10-a.html
If you're on W11:
To restore Windows 11 default themes, follow these steps: 1. Open Settings and click on Personalization. 2. Click on the Themes page on the right side. 3. Click on the "Restore Default" button below the list of icons to restore the default icons. 4. To let themes change the desktop icons, ensure the "Allow themes to change desktop icons" checkbox is checked. 5. Click the "OK" button when finished changing the desktop icons. 6. To change the default theme, either click on the "Apply" button in the Microsoft Store or go to Settings > Personalization > Themes. 7. Select the new theme design to apply it. 8. To change a theme's color scheme, click on the "Choose your mode" drop-down menu and select the "Dark" option. 9. Turn on the "Show accent color on Start and taskbar" option to apply any accent color you choose to the Start menu and taskbar. 10. To restore a theme's default color scheme, select "Automatic" on the Accent color drop-down menu.
Hope this helps. Next time, if you decide to uninstall Windowblinds first change the skin to the default theme.