This option may not be available in your theme's Theme Customizer. In this case, you can try one of the following methods.
Change background color with Full Site Editor
The Full Site Editor (FSE) is a block-based WordPress theme editor that allows you to edit the background color of your website. It offers various blocks to customize the website design and is similar to using the WordPress block editor.
The full site editor is currently available in select philippines numbers WordPress themes , such as the Twenty Twenty-Two theme. To change the background color, you can go to Appearance ” Editor in your WordPress dashboard.
Open editor from appearance dashboard
Once you are in the full site editor , you can change the background color of each individual block.
First, select a block you want to edit, then go to the “Color” section in the settings panel on the right and click on the “Background” option to choose a color.
On the other hand, if you want to add a background color that appears behind all blocks, you can add a cover block.
First, click on the “+” sign at the top and add the “Cover” block.
Add a cover block
Next, you will see the 'Cover' block in the theme's template with some background color options to choose from.