API Proposal - example code included

public static class ProposalExtensions
    {
        public static void JustShowMeTheCode(IDbConnection cn)
        {
            var result = cn.Query(
                // allows to use anonymous type as result
                template: new { EmployeeName = "" }, 
                param: new { EmployeeAge = 26 },
                // allows to use 'nameof' for column names and parameter names 
                sql: (t, p) => $"select e.name as {nameof(t.EmployeeName)} from tbl_emp e where e.age>@{nameof(p.EmployeeAge)}");
            foreach (var item in result)
            {
                Console.WriteLine(item.EmployeeName);
            }
        }

        public static IEnumerable<T> Query<T,TParams>(this IDbConnection cnn, T template, Func<T,TParams,string> sql, TParams param,  IDbTransaction? transaction = null, bool buffered = true, int? commandTimeout = null, CommandType? commandType = null)
        {
            return cnn.Query<T>(sql(default(T),default(TParams)),param,transaction,buffered,commandTimeout,commandType);
        }

        public static IEnumerable<T> Query<T>(this IDbConnection cnn, T template, Func<T,string> sql, IDbTransaction? transaction = null, bool buffered = true, int? commandTimeout = null, CommandType? commandType = null)
        {
            return cnn.Query<T>(sql(default(T)), param:null, transaction, buffered, commandTimeout, commandType);
        }
    }

Start by reviewing the IDbConnection Query extension examples shown in the issue and the proposed overload signatures. The issue does not name repository files, tests, or acceptance criteria, so clarify the intended API and expected behavior before identifying an implementation location or defining what done means.