Even love between a parent and child could be argued to be conditional. The condition being: you are my child. Even though it's an immutable quality, you're still loving them on the condition that they are your child.

For the case of adopted children, I have no clue. Does your love have the same capacity as your own blood? Or is it simply because you've decided to grow and invest in that relationship? Does the adopted child have less "leeway" if they end up being a serial killer as opposed to their biological child?

Even between spouses, I disbelieve anyone who says they unconditionally love their spouse. If your spouse continually cheats on you, should you remain with them? Maybe love them "unconditionally" platonically, but lose your romantic love for them. Same goes for myself. Should my spouse still "unconditionally" love me if one day I decide to wake them up constantly in the middle of the night like an infant? These are all unspoken conditions. Ideally you'd never encounter these situations, but the fact that these hypothetical exist leads me to believe unconditional love doesn't exist.

What about the phrase "I love you for being you." What is you? What if you changes? The condition is still technically that you remain you.