The Douay-Rheims is my favorite version, but I also read, for comparisons, two Aramaic to English translations, two King James Versions, the RSV, The Greek New Testament Interlinear, the Vulgate, and for the Old Testament I occasionally refer to the Septuagint with Strong’s numbers.
I would not suggest that Christ’s teachings contradict one another. You have to read a verse in light of the passage, the passage in light of the chapter, the chapter in light of book, the book in light of the Testament, and the Testament in light of the other Testament.
When I have questions, I look to see if the Church has an ‘official’ interpretation in the Catechism. I will also look to the early Church fathers, up to the men of the Church of present times.
When Christ commands us to love one another, as He loves us, it’s unconditional. Remember, He also taught us to pray, ‘forgive us our trespasses, as we forgive those who trespass against us.’