Why are Angular material menu items not showing?

I have this problem, and the point is that everything is supposed to be done correctly. When I try to see a menu, as specified in the documentation of Angular material components, they are not seen. I attach my code to give you an idea:

<header id="mainHeader">
  <mat-toolbar color="primary">
    <mat-menu #menu="matMenu">
      <button mat-menu-item>Item 1</button>
      <button mat-menu-item>Item 2</button>
    </mat-menu>
  </mat-toolbar>
</header>
<router-outlet></router-outlet>
<footer>
  <mat-toolbar color="accent">
    <small></small>
  </mat-toolbar>
</footer>

This you see is my app.component.html. Now I attach the code of the app.component.ts:

import { Component } from '@angular/core';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.sass']
})
export class AppComponent {
  title = 'TITULO';
}

The fact is that I haven't touched anything, I've done it directly in a project from scratch to see if I could find the reason, but nothing...

I attach the codeapp.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { BrowserAnimationsModule } from '@angular/platform-browser/animations';

import { MatMenuModule } from '@angular/material/menu';
import { MatToolbarModule } from '@angular/material/toolbar';
import { MatButtonModule } from '@angular/material/button';
import { MatFormFieldModule } from '@angular/material/form-field';
import { MatIconModule } from '@angular/material/icon';
import { MatButtonToggleModule } from '@angular/material/button-toggle';
import { MatPaginatorModule } from '@angular/material/paginator';
import { MatTableModule } from '@angular/material/table';
import { MatCheckboxModule } from '@angular/material/checkbox';
import { MatAutocompleteModule } from '@angular/material/autocomplete';
import { MatDatepickerModule } from '@angular/material/datepicker';
import { MatInputModule } from '@angular/material/input';
import { MatRadioModule } from '@angular/material/radio';
import { MatSelectModule } from '@angular/material/select';
import { MatSliderModule } from '@angular/material/slider';
import { MatSlideToggleModule } from '@angular/material/slide-toggle';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    AppRoutingModule,
    BrowserAnimationsModule,
    MatMenuModule,
    MatToolbarModule,
    MatButtonModule,
    MatFormFieldModule,
    MatIconModule,
    MatButtonToggleModule,
    MatPaginatorModule,
    MatTableModule,
    MatCheckboxModule,
    MatAutocompleteModule,
    MatDatepickerModule,
    MatInputModule,
    MatRadioModule,
    MatSelectModule,
    MatSliderModule,
    MatSlideToggleModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

Package.json:

  "dependencies": {
    "@angular/animations": "~9.0.2",
    "@angular/cdk": "^9.1.0",
    "@angular/common": "~9.0.2",
    "@angular/compiler": "~9.0.2",
    "@angular/core": "~9.0.2",
    "@angular/forms": "~9.0.2",
    "@angular/material": "^9.1.0",
    "@angular/platform-browser": "~9.0.2",
    "@angular/platform-browser-dynamic": "~9.0.2",
    "@angular/router": "~9.0.2",
    "rxjs": "~6.5.4",
    "tslib": "^1.10.0",
    "zone.js": "~0.10.2"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "~0.900.3",
    "@angular/cli": "~9.0.3",
    "@angular/compiler-cli": "~9.0.2",
    "@angular/language-service": "~9.0.2",
    "@types/node": "^12.11.1",
    "@types/jasmine": "~3.5.0",
    "@types/jasminewd2": "~2.0.3",
    "codelyzer": "^5.1.2",
    "jasmine-core": "~3.5.0",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~4.3.0",
    "karma-chrome-launcher": "~3.1.0",
    "karma-coverage-istanbul-reporter": "~2.1.0",
    "karma-jasmine": "~2.0.1",
    "karma-jasmine-html-reporter": "^1.4.2",
    "protractor": "~5.4.3",
    "ts-node": "~8.3.0",
    "tslint": "~5.18.0",
    "typescript": "~3.7.5"
  }

Does anyone see if I'm missing something or doing it incorrectly? I've never had this problem before, but I've been doing tests for a while, and I can't figure it out. Thanks in advance for the attention given.