Can't cast Int to Decimal with EF Core?

I am trying to solve an issue I have with pulling large ints (22+ digits) into ASP.Net with Entity Framework Core from a MySQL database.

EF Core does not support BigInteger and the suggestions I received where to use decimal instead. However, when using decimal types on my entities, I always receive the following exception when trying to select from the DB:

System.InvalidCastException: Unable to cast object of type 'System.Int32' to type 'System.Decimal'

In the Database the columns are INT(25) and in my models the type is decimal, here is an example model:

[Table("alliance_reputation_rankings")]
public class AllianceReputationRank
{
    [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
    [Column("date")]
    public DateTime Date { get; set; }

    [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
    [Column("world")]
    public int World { get; set; }

    [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
    [Column("alliance")]
    public string Alliance { get; set; }

    [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
    [Column("rank")]
    public int Rank { get; set; }

    [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
    [Column("reputation")]
    public decimal Reputation { get; set; }

    [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
    [Key]
    [Column("entry_id")]
    public int EntryId { get; set; }
}

I cannot select the Reputation property using EF Core. Even if I try and use (decimal) before the property to cast it:

Rough example of a select:

_context.AllianceReputationRankings
   .Where(p => p.Date == rank.Date && p.Alliance== rank.Alliance && p.World == rank.World)
                                   .Select(pl =>  new AllianceReputationRank
                                   {
                                       Date = pl.Date,
                                       World = pl.World,
                                       Alliance = pl.Alliance,
                                       Reputation = (decimal)pl.Reputation
                                   }
                                   ).FirstOrDefault();

How can I use decimals in my models to bring in large ints from the database? If I cannot use decimals, how can I use large numbers with EF Core?