Discovering the enemies of the children of Israel and what to do with them was always a black and white thing in the OT. They were to kill all of the "-ites" specifically named. In Deut 7:1-2 seven peoples are named in the Promised Land to be killed. Deut 20:10-18 lists only 6, excluding the Girgashites, but provides more detail on how they were to deal with enemies or potential enemies. The ones nearby, that is in the Promised Land itself [the 6 or 7] are to be exterminated, killing men, women, children and cattle, that is each and every creature that lives and breathes. With other enemies not so close, and not among those named, only the adult males were to be killed. The women, children and cattle were to be retained alive for themselves as spoils of war.
The "-ites" 6 or 7 types and shadows for us could correspond to the abominations named here:
“These six things doth the LORD hate: yea, seven are an abomination unto him:
A proud look, a lying tongue, and hands that shed innocent blood,
An heart that deviseth wicked imaginations, feet that be swift in running to mischief,
A false witness that speaketh lies, and he that soweth discord among brethren.” Prov 6:16-19
The children of Israel were to kill the peoples within in the Promised Land completely. We are to kill the abominations of which are within the "old man" of each of us described by Paul.
"Knowing this, that our old man is crucified with him, that the body of sin might be destroyed, that henceforth we should not serve sin." Rom 6:6
Peoples outside the Promised Land were given an opportunity to make peace with the Israelites. Similarly we give those outside of us [perhaps the Body of Christ?] opportunity to make peace with us.
We still are to hate our enemies but only the ones God clearly identifies to us through the Holy Spirit. Our primary enemies that we know are on the inside of us. In the OT God through His prophets, priests, judges & kings [Moses, Joshua, David and others] let everyone know who their primary enemies were. Through the anointed writers of scripture and the leading of the Holy Spirit we are similarly given to know who our enemies are. Enemies outside of me [within other persons] should also be approached in peace because some or all of them have hope. We are to love them until and if we are led by the Holy Spirit to understand that there is nothing to love and we are to hate them.
God knows from the beginning who to love and who to hate. We do not!
"I have loved you, saith the LORD. Yet ye say, Wherein hast thou loved us? Was not Esau Jacob's brother? saith the LORD: yet I loved Jacob,
And I hated Esau, and laid his mountains and his heritage waste for the dragons of the wilderness" Malachi 1:2-3
[As a footnote to this, we need to remember what women and children are spiritually and treat them accordingly. Someone acting in the role of a man {who should be God's ministers speaking His Word (or not)... speaking as Head} (which could include physical women), as God sees it, but who actually opposes God and God's people (false prophets, pastors ministers, et al) is to be hated and killed (spiritually, not physically).
Someone in the role of a woman or child {who should be God's people or the subjected Body of Christ ... not the Head} (which should include any immature person of any physical age or gender) should receive mercy among those acting in the roles of spiritual men but opposing God should receive mercy and be trained hopefully to stand on the Lord's side. This subject I mention here because it has helped me and may help others to understand the lessons available from the OT if and when they are able to understand them]