How to replace (SIMILAR TO + regular expression) with LIKE or ~ in PostgreSQL?
LIKE is much less flexible than SIMILAR TO.  In general there is going to be no formulaic way to downgrade from SIMILAR TO to LIKE.  Based on your example, it might take like 34 (4*4 + 3*3 + 3*3) different ORed together LIKE to accomplish this.  For example, your first expression in the OR branch gets to pair 3 alternatives plus the empty possibility (so 4 total) at the beginning with another 4 at the end, so that would expand to 16.


  I read many advises to avoid using SIMILAR TO and to replace it with simple LIKE for performance issues


This advice would only apply if there is a simple like which does the same job.  But in general, tuning should be based on evidence, not on rumors.  So to start with, do you actually have a performance problem?