Different prefixes of a candidate key column and a referencing foreign key column

WITH 
fk_constraint_names AS (select 
o.conname,
(select nspname from pg_namespace where oid=f.relnamespace) as foreign_ns,
f.relname as foreign_table,
(select a.attname from pg_attribute a where a.attrelid = f.oid and a.attnum = o.confkey[1] and a.attisdropped = false) as foreign_colname,
(select nspname from pg_namespace where oid=c.relnamespace) as target_ns,
c.relname as target_table, 
(select a.attname from pg_attribute a where a.attrelid = c.oid and a.attnum = o.conkey[1] and a.attisdropped = false) as target_colname
from pg_constraint o inner join pg_class c on c.oid = o.conrelid
inner join pg_class f on f.oid = o.confrelid
where o.contype = 'f')
SELECT foreign_ns, foreign_table, foreign_colname, target_ns, target_table, target_colname
FROM fk_constraint_names
WHERE 
lower(regexp_replace(foreign_colname,'^(([[:alpha:]]|_)[[:alnum:]]{0,4})_.*','\1'))<>lower(regexp_replace(target_colname,'^(([[:alpha:]]|_)[[:alnum:]]{0,4})_.*','\1'))
AND lower(regexp_replace(foreign_colname,'^(([[:alpha:]]|_)[[:alnum:]]{0,4})_.*','\1')) IN ('id','kood','code','nr')
AND lower(regexp_replace(target_colname,'^(([[:alpha:]]|_)[[:alnum:]]{0,4})_.*','\1')) IN ('id','kood','code','nr')
ORDER BY target_ns, target_table;