The law against charging interest was under Moses’ law so it was abolished along with the rest when Jesus died. Useful principles added, covering not interest specifically, but condemning greed (which is foundational to late stage capitalism…); 1 Tim 6:10, Matt 6:24
There are plenty of other examples of modern Christians picking and choosing though. Starting with ignoring the above call to charity (if we read it that way). There are many calls to give freely, yet most modern Christian’s are content with pretty minor giving overall. Or we could talk about how “turn the other cheek” aligns with the distinct non-pacifism that permeates modern Christianity. Or we could talk about taking oaths, divorce, head coverings by women in church, embrace of community property. Etc.
Christian scholars regularly debate how to interpret portions of the Bible. I’m not sure what they are doing if it’s clear and easy to adhere to.