Should my methods return concrete classes or interfaces?

I'm building a ASP.NET Core Web API and the application consists of 3 main modules.

1. Data module: Contains the entities and DbContext
2. Web API: Contains the controllers
3. Service module: Contains all the data processing logic between the data module and the web API.

I'm not using repository pattern to access data from the service module, and I was thinking about fully exposing my DbContext to the service module to query it directly from the service module. Later, I created an interface and defined some methods to expose only the DbSet<T> or IQueryable<T> to its caller,

public interface IShareableContext
{
    //option 1
    DbSet<TEntity> ExposeDbSet<TEntity>() where TEntity : class;
    //option 2
    IQueryable<TEntity> ExposeIQueryable<TEntity>() where TEntity : class;
    Task SaveChangesAsync();
}

internal class DefaultSharedContext : IShareableContext
{
    private readonly ApplicationDbContext _ctx;

    public DefaultSharedContext(ApplicationDbContext ctx)
    {
        _ctx = ctx;
    }

    public DbSet<TEntity> ExposeDbSet<TEntity>() where TEntity : class
    {
        return _ctx.Set<TEntity>();
    }

    public IQueryable<TEntity> ExposeIQueryable<TEntity>() where TEntity : class
    {
        return _ctx.Set<TEntity>();
    }

    public async Task SaveChangesAsync()
    {
        await _ctx.SaveChangesAsync();
    }
}

And this interface and implementation will be registered on the dependency injection container to be used by the service module. But I'm still wondering whether should I choose option 1 method or option 2 method in my IShareableContext interface. Especially about returning a concrete class vs interface. If I'm returning IQueryable<T> I will have to define and implement some additional methods for behaviors such as add, delete and modify since IQueryable<T> does not define them. But I can't figure out whether staying away from returning DbSet<T> is worth for having to implement a few more behaviors.