slow query

Dear I have a question to ask you
I am having a slow problem with a query and I am seeing with the explain
that the current cost and time differ by 4 times
Postgres version 9.5.16 in centos 7.6
To try to solve this run the statistics to the table and the same problem
remains
It's a very big table 2 billion tuples
Do you have any idea what I can do to improve
Thank you very much for your time
Any data you need I can provide

I share a part of the explain

Hash Right Join (cost=11114339.65..12172907.42 rows=886647 width=158)
(actual time=1906344.617..1963668.889 rows=3362294 loops=1)"
" Output: ba.bus_ent_inst_id_auto, ba.att_value_1,
ba.att_value_num_1, att_call.ent_inst_att_str_value,
att_nro.ent_inst_att_str_value, att_bis.ent_inst_att_str_value,
att_pad.ent_inst_att_str_value, att_manz.ent_inst_att_str_value, att_a
(...)"
" Hash Cond: ((att_barr.env_id = ba.env_id) AND
(att_barr.bus_ent_inst_id = ba.bus_ent_inst_id_auto))"
" Buffers: shared hit=5814458 read=1033324 dirtied=790"

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Sent from: https://www.postgresql-archive.org/PostgreSQL-performance-f2050081.html