DATE_PART function not working after migrating to hibernate 6

Question

My query is to get the number of days from the difference between two date fields and compare it to a specified value.

  select
      *
    from
        transaction transactio0_ 
    where
        transactio0_.order_status=? 
        and (
            transactio0_.date_start between ? and ?
        ) 
        or DATE_PART(?,transactio0_.date_end-transactio0_.date_start)=100.0;

Since there will be a variable amount of conditions, I am unable to use native query, therefore specification is required.

I have provided the specification condition as below

  spec = spec.and((root, query, builder) -> {
                return builder.equal(
                        builder.function("DATE_PART", Double.class, builder.literal("day"),
                                builder.diff(endDate,startDate )),
                        filter.orderPendingDays());
            });

The query was originally generated as follows. DATE_PART('day',transactio0_.date_end-transactio0_.date_start)

I was using hibernate 5, then after switching to hibernate 6, the following things occurred.

This is how the query is generated after migration. DATE_PART('day',extract(epoch from t1_0.date_end-t1_0.date_start)*1e9)

Currently, an error is being thrown.

Caused by: org.postgresql.util.PSQLException: ERROR: function date_part(unknown, double precision) does not exist

Could someone please explain the issue to me?