the Bible is either inspired and infalible and as such should be taken seriously or it is not.
If it is not inspired then the reasons for the text become more sinister and less benevolent. The purpose of the characters of God and the Devil then take on a new perspective. As so many people trust the Bible it needs to stand up to scrutiny and it is appropriate that questions are asked and answered. The Bible does justify extremes for example killing nations including women and children in the name of God. It sets high standards for people to live by and is used as the basis of condemning those who do not. I have lived by these rules and know how deeply they impact on your life when misapplied.
Please do not try to read my mind or make assumptions about what I may or may not believe or want. I have spent over 40 years believing that the Devil has been operating in the world. I sincerely believed the scriptures you quoted. The only change is now I do not take things at face value and am prepared to ask myself the difficult questions.