Migrating from EF Core 2 to EF Core 3

Question

After upgrading my project from (dotnet core 2/ef core 2) to (dotnet core 3/ef core 3) almost all of my entity framework LINQ queries are broken. while I already read this it's still unclear to know what to do.

Here are some examples that I have problem with:

var league = await dbContext.League.LastAsync();

While this code worked just fine in ef core 2 it throws exception in ef core 3. The only workaround I could find about this was the following code which is still not what I want since it's not async like before.

var league = dbContext.League.AsEnumerable().Last();

Another example that throws the same exception is the following code:

var user = await dbContext.User.FirstOrDefaultAsync(u =>
                u.UserId == userId && string.Equals(u.Token, token, StringComparison.InvariantCulture));

I still can use AsEnumerable() but the async version of FirstOrDefault is not available there so that's not an option. can somebody guide me with this ?

EDIT
Here's the exception:

System.InvalidOperationException: The LINQ expression 'Last<League>(DbSet<League>)' could not be translated. Either rewrite the query in a form that can be translated, or switch to client evaluation explicitly by inserting a call to either AsEnumerable(), AsAsyncEnumerable(), ToList(), or ToListAsync(). See https://go.microsoft.com/fwlink/?linkid=2101038 for more information.