The issue was resolved by changing the following parameters

* `work_mem`  changed from 4mb to 50 mb
* `random_Page_size` changed to 1 from 4
* `max_wal_size` reduced to 128 mb from 2 gb
* `cpu_index_tuple_cost` to 0.003

Also changed the following as suggested by @Gerad H.pille

     max_parallel__Workers_per_Gather 
     max_parallel_maintainence_workers