LWC get url parameters in Community

If the question was if the LWC Framework provide an utility - then no not that i am aware of.

Which means you can use every js snippet you will find somewhere in the web like

    parameters = {};

    connectedCallback() {

        this.parameters = this.getQueryParameters();
        console.log(this.parameters);
    }

    getQueryParameters() {

        var params = {};
        var search = location.search.substring(1);

        if (search) {
            params = JSON.parse('{"' + search.replace(/&/g, '","').replace(/=/g, '":"') + '"}', (key, value) => {
                return key === "" ? value : decodeURIComponent(value)
            });
        }

        return params;
    }

That will return you an key/value pair of your parameters for further usage in your component

Another approach with using URL.searchParams:

The searchParams readonly property of the URL interface returns a URLSearchParams object allowing access to the GET decoded query arguments contained in the URL.

connectedCallback() {
    const param = 'test';
    const paramValue = this.getUrlParamValue(window.location.href, param);
}

getUrlParamValue(url, key) {
    return new URL(url).searchParams.get(key);
}

The best way to get params from URL is use CurrentPageRefference.

currentPageReference.state allows you to get params.

import { LightningElement, wire } from 'lwc';
import { CurrentPageReference } from 'lightning/navigation';

export default class Test extends LightningElement {

    currentPageReference = null; 
    urlStateParameters = null;

    urlId = null;
    urlLanguage = null;
    urlType = null;

    @wire(CurrentPageReference)
    getStateParameters(currentPageReference) {
       if (currentPageReference) {
          this.urlStateParameters = currentPageReference.state;
          this.setParametersBasedOnUrl();
       }
    }

    setParametersBasedOnUrl() {
       this.urlId = this.urlStateParameters.id || null;
       this.urlLanguage = this.urlStateParameters.lang || null;
       this.urlType = this.urlStateParameters.type || '10';
    }
}

More details you can find here https://salesforceprofs.com/how-to-get-url-params-in-lwc/