See https://indepth.dev/angulars-root-and-any-provider-scopes/.

'any' provider scope: config.service.ts

import { Injectable, Inject } from '@angular/core';

import { configToken } from './config.token';
import { Config } from './config';

@Injectable({
  providedIn: 'any', // 👈 Tree-shakable, only bundled if used
})
export class ConfigService {
  constructor(@Inject(configToken) private config: Config) {
    console.log('new instance is created');
  }

  getValue() {
    return this.config;
  }
}

'any' provider scope: department.module.ts

import { CommonModule } from '@angular/common';
import { NgModule } from '@angular/core';

import { configToken } from '../shared/config.token';
import { Config } from '../shared/config';
import { DepartmentRoutingModule } from './department-routing.module';
import { DepartmentComponent } from './department.component';

export const configValue: Config = {
  apiEndPoint: 'xyz.com',
  timeout: 4000,
};

@NgModule({
  declarations: [
    DepartmentComponent,
  ],
  imports: [
    CommonModule,
    DepartmentRoutingModule,
  ],
  providers: [
    {
      provide: configToken, useValue: configValue,
    },
  ],
})
export class DepartmentModule { }

Feature module provider: config.service.ts

import { Injectable, Inject } from '@angular/core';

import { configToken } from './config.token';
import { Config } from './config';

@Injectable()
export class ConfigService {
  constructor(@Inject(configToken) private config: Config) {
    console.log('new instance is created');
  }

  getValue() {
    return this.config;
  }
}

Feature module provider: department.module.ts

import { CommonModule } from '@angular/common';
import { NgModule } from '@angular/core';

import { ConfigService } from '../shared/config.service';
import { configToken } from '../shared/config.token';
import { Config } from '../shared/config';
import { DepartmentRoutingModule } from './department-routing.module';
import { DepartmentComponent } from './department.component';

export const configValue: Config = {
  apiEndPoint: 'xyz.com',
  timeout: 4000,
};

@NgModule({
  declarations: [DepartmentComponent],
  imports: [
    CommonModule,
    DepartmentRoutingModule,
  ],
  providers: [
    { provide: configToken, useValue: configValue },
    ConfigService, // 👈 Always bundled, even if unused
  ],
})
export class DepartmentModule { }

forChild pattern: config.module.ts

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

import { ConfigService } from './config.service';

@NgModule()
export class ConfigModule {
  static forChild(): ModuleWithProviders<ConfigModule> {
    return {
      ngModule: ConfigChildModule,
      providers: [
        ConfigService, // 👈 Always bundled, even if unused
      ],
    };
  }
}

forChild pattern: config.service.ts

import { Injectable, Inject } from '@angular/core';

import { configToken } from './config.token';
import { Config } from './config';

@Injectable()
export class ConfigService {
  constructor(@Inject(configToken) private config: Config) {
    console.log('new instance is created');
  }

  getValue() {
    return this.config;
  }
}

forChild pattern: department.module.ts

import { CommonModule } from '@angular/common';
import { NgModule } from '@angular/core';

import { ConfigModule } from '../shared/config.module';
import { configToken } from '../shared/config.token';
import { Config } from '../shared/config';
import { DepartmentRoutingModule } from './department-routing.module';
import { DepartmentComponent } from './department.component';

export const configValue: Config = {
  apiEndPoint: 'xyz.com',
  timeout: 4000,
};

@NgModule({
  declarations: [DepartmentComponent],
  imports: [
    ConfigModule.forChild(), // 👈
    CommonModule,
    DepartmentRoutingModule,
  ],
  providers: [
    {
      provide: configToken, useValue: configValue,
    },
  ],
})
export class DepartmentModule { }

Service module provider: config.service.ts

import { Injectable, Inject } from '@angular/core';

import { configToken } from './config.token';
import { Config } from './config';

@Injectable()
export class ConfigService {
  constructor(@Inject(configToken) private config: Config) {
    console.log('new instance is created');
  }

  getValue() {
    return this.config;
  }
}

Service module: config-service.module.ts

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

import { ConfigService } from './config.service';

@NgModule({
  providers: [
    ConfigService, // 👈 Always bundled, even if unused
  ],
})
export class ConfigServiceModule {
  static forChild(): ModuleWithProviders<ConfigModule> {
    return {
      ngModule: ConfigChildModule,
      
    };
  }
}

Service module: config.service.ts

import { Injectable, Inject } from '@angular/core';

import { configToken } from './config.token';
import { Config } from './config';

@Injectable()
export class ConfigService {
  constructor(@Inject(configToken) private config: Config) {
    console.log('new instance is created');
  }

  getValue() {
    return this.config;
  }
}

Service module: department.module.ts

import { CommonModule } from '@angular/common';
import { NgModule } from '@angular/core';

import { ConfigServiceModule } from '../shared/config-service.module';
import { configToken } from '../shared/config.token';
import { Config } from '../shared/config';
import { DepartmentRoutingModule } from './department-routing.module';
import { DepartmentComponent } from './department.component';

export const configValue: Config = {
  apiEndPoint: 'xyz.com',
  timeout: 4000,
};

@NgModule({
  declarations: [DepartmentComponent],
  imports: [
    ConfigServiceModule, // 👈
    CommonModule,
    DepartmentRoutingModule,
  ],
  providers: [
    {
      provide: configToken, useValue: configValue,
    },
  ],
})
export class DepartmentModule { }