If everything has a purpose then evil doesn't exist

[R-Farmer]

God allows mankind to Love their sin. Which is what evil is. God does not put this love of sin in our heart. That is something we do on our own.

Of course God puts the love of sin in our heart. Love of sin is evil and God creates evil. Therefore God creates the love of sin. Isaiah 45:7.

Boru

the word evil in the hebrew has several different meaning. It is a literal catch phrase that is used to describe anything bad undesirable or unwanted.

Here is the general definition:רַע raʻ, rah; from H7489; bad or (as noun) evil (natural or moral):—adversity, affliction, bad, calamity, displease(-ure), distress, evil((-favouredness), man, thing), +exceedingly, × great, grief(-vous), harm, heavy, hurt(-ful), ill (favoured), + mark, mischief(-vous), misery, naught(-ty), noisome, + not please, sad(-ly), sore, sorrow, trouble, vex, wicked(-ly, -ness, one), worse(-st), wretchedness, wrong. (Including feminine raaah; as adjective or noun.)

here is the definition in context:
†1. evil, distress, adversity: יָרֵא רַע fear evil Psalm 23:4; Zephaniah 3:15; בּוֺרֵא רָ֑ע Isaiah 45:7 (of God), הביא רע 

https://www.blueletterbible.org/lexicon/...v/wlc/0-1/

While evil is a possible translation, the context supports the idea of calamity as in god is bringing the pain/He will do whatever it takes to crush the enemy of his servant Cyrus whom God is fully supporting. That he is willing to rain down evil and or calamity to the nations that stand in opposition to his servant Cyrus.