Во-первых, что касается
Roaming work_mem = 100000
sort_mem = 10240
shared_buffers =22937 прочтите следующее:

Documentation SaysSpecifies the amount of memory to be used by internal sort
operations and hash tables before switching to temporary disk
files. The value is specified in kilobytes, and defaults to 1024
kilobytes (1 MB). Note that for a complex query, several sort or
hash operations might be running in parallel; each one will be
allowed to use as much memory as this value specifies before it
starts to put data into temporary files. Also, several running
sessions could be doing such operations concurrently. So the
total memory used could be many times the value of
work_mem; it is necessary to keep this fact in mind when
choosing the value. Sort operations are used for ORDER BY,
DISTINCT, and merge joins. Hash tables are used in hash
joins, hashbased aggregation, and hashbased processing of IN
subqueries.
CommentsFormerly sort_mem, this setting name has been changed to reflect
its expanded role in governing more than just sorts.
Work_mem is a direct tradeoff. Adjust it upwards for: large
databases, complex queries, lots of available RAM. Adjust it
downwards for: low available RAM, or many concurrent users.
Finding the right balance spot can be hard.
Another way to set this value is to monitor the Postgres temp files
(in PGDATA/base/DB_OID/pgsql_tmp) and adjust sort_mem
upward if you see a lot of queries swapping from these temp files.
Also keep in mind that this parameter can be adjusted per
connection. So if you only have a few really large queries, you can
increase the work_mem for them before query execution, and leave
it low for the rest of the connections.

Ваше sort_mem на самом деле либо игнорируется вообще, либо переустанавливает work_mem , что еще хуже. Уберите, а если интересует, то сделайте запрос, какое значение фактически используется.
Во-вторых, ваши запросы из-за LIKE виполняются посл. сканированием. Замените двумя неравенствами, чтобы использовать индекс.