MyLWC.css

.DXPTheme * {
  /**
  awesome styling, I don't know so much about CSS
  */
}

MyLWC.html

<template>
    <lightning-card class={theme}>
    </lightning-card>
</template>

MyLWC.js

export default class UploadFilesToS3 extends NavigationMixin(LightningElement) {
	@api
	theme;
  /**
  .....
  */
}

MyLWC.js-meta.xml

<?xml version="1.0" encoding="UTF-8"?>
<LightningComponentBundle xmlns="http://soap.sforce.com/2006/04/metadata">
    <apiVersion>51.0</apiVersion>
    <isExposed>true</isExposed>
    <targets>
        <target>lightning__RecordPage</target>
        <target>lightningCommunity__Page</target>
    </targets>
    <targetConfigs>
        <targetConfig targets="lightning__RecordPage">
            <property name="theme" type="String" default="defaultTheme" label="Theme for LWC Styling" required="true" description="Put your brain to work" />
            <!-- <objects>
                <object>Order</object>
            </objects> -->
            <supportedFormFactors>
                <supportedFormFactor type="Small" />
                <supportedFormFactor type="Large" />
            </supportedFormFactors>
        </targetConfig>
        <targetConfig targets="lightningCommunity__Page">
            <property name="theme" type="String" default="DXPTheme" label="Theme for the Developer Experience Site" required="true" description="Put your brain to work" />
            <supportedFormFactors>
                <supportedFormFactor type="Small" />
                <supportedFormFactor type="Large" />
            </supportedFormFactors>
        </targetConfig>
    </targetConfigs>
</LightningComponentBundle>