Preserve query parameters and fragments across navigations in Angular

// Set our navigation extras object
// that passes on our global query params and fragment
let navigationExtras: NavigationExtras = {
  queryParamsHandling: 'preserve',
  preserveFragment: true
};

// Redirect the user
this.router.navigateByUrl(redirect, navigationExtras);

The queryParamsHandling feature also provides a merge option, which will preserve and combine the current query parameters with any provided query parameters when navigating.

References
https://angular.io/guide/router#query-parameters-and-fragments