diff --git a/Dapper/SqlMapper.cs b/Dapper/SqlMapper.cs
index d23e949a5..e5d8f8b70 100644
--- a/Dapper/SqlMapper.cs
+++ b/Dapper/SqlMapper.cs
@@ -463,6 +463,10 @@ public static void SetDbType(IDataParameter parameter, object value)
             handler = null;
             var nullUnderlyingType = Nullable.GetUnderlyingType(type);
             if (nullUnderlyingType is not null) type = nullUnderlyingType;
+            if (typeHandlers.TryGetValue(type, out handler))
+            {
+                return DbType.Object;
+            }
             if (type.IsEnum && !typeMap.ContainsKey(type))
             {
                 type = Enum.GetUnderlyingType(type);
@@ -479,10 +483,6 @@ public static void SetDbType(IDataParameter parameter, object value)
             {
                 return DbType.Binary;
             }
-            if (typeHandlers.TryGetValue(type, out handler))
-            {
-                return DbType.Object;
-            }
             if (typeof(IEnumerable).IsAssignableFrom(type))
             {
                 // auto-detect things like IEnumerable<SqlDataRecord> as a family
@@ -2749,7 +2749,7 @@ private static bool IsValueTuple(Type? type) => (type?.IsValueType == true
                     var nullType = Nullable.GetUnderlyingType(propType);
                     bool callSanitize = false;
 
-                    if ((nullType ?? propType).IsEnum)
+                    if ((nullType ?? propType).IsEnum && handler == null)
                     {
                         if (nullType is not null)
                         {