EntityType: FruitJam (Dictionary<string, object>) CLR Type: Dictionary<string, object>
    Properties: 
      FruitsId (no field, Guid) Indexer Required PK FK AfterSave:Throw
      JamsId (no field, Guid) Indexer Required PK FK Index AfterSave:Throw
    Keys: 
      FruitsId, JamsId PK
    Foreign keys: 
      FruitJam (Dictionary<string, object>) {'FruitsId'} -> Fruit {'Id'} Required Cascade
      FruitJam (Dictionary<string, object>) {'JamsId'} -> Jam {'Id'} Required Cascade
    Indexes: 
      JamsId

  EntityType: FruitJam (Dictionary<string, object>) CLR Type: Dictionary<string, object>
    Properties: 
      FruitsId (no field, Guid) Indexer Required PK AfterSave:Throw ValueGenerated.OnAdd
      FruitsId1 (no field, Guid) Indexer Required FK Index
      JamsId (no field, Guid) Indexer Required FK Index
    Keys: 
      FruitsId PK
    Foreign keys: 
      FruitJam (Dictionary<string, object>) {'FruitsId1'} -> Fruit {'Id'} Required Cascade
      FruitJam (Dictionary<string, object>) {'JamsId'} -> Jam {'Id'} Required Cascade
    Indexes: 
      FruitsId1 FruitsId1_1
      JamsId JamsId_1

await using var db = new DbPreserves();

Console.WriteLine(db.Model.ToDebugString());

public class DbPreserves : DbContext
{
    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        => optionsBuilder.UseMongoDB("mongodb://localhost:56668/?directConnection=true", "Fruity5");

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Jam>().HasMany(e => e.Fruits).WithMany(e => e.Jams);
    }
}

public class Fruit
{
    public Guid Id { get; set; }
    public string Name { get; set; } = null!;
    public List<Jam> Jams { get; } = new();
}

public class Jam
{
    public Guid Id { get; set; }
    public string Name { get; set; } = null!;
    public List<Fruit> Fruits { get; } = new();
}