If there is no real "if," (if all is irrevockably and unchangeably predestined by decree) then the Bible verses which speak of "ifs and thens" are not true. They are illusory statements. But in those verses where God uses if-then statements, God's actions are clearly conditioned upon the actions of men. So, unless God was intending to mislead the readers of the Bible, the If-Then statements of God (all 300+ of them) attest to that fact.
Now the question is how do you deal with that fact?
The Bible is written for human beings to understand and follow. If we had no language, it would be a picture book, telling us the same things -- how to live and what God expects of us.
The greater reality is that God, creator of heaven and earth and all else for all time and beyond, knows EVERYTHING. Always has. All ways; always.
If you blink, He knows it. He fashioned your eyelids; He created the breeze that blows by your face, causing you to squint in the sunlight and BLINK.
If you stifle a sneeze, it isn't because God changed His mind. You were never going to sneeze in the first place.
God bless you (just in case).
Conditional statements can work for illustrative purposes as well as instructive. The verses above readily demonstrate that. The destruction of Sodom occurred hundreds of years before these statements. It was a done deal, and yet Jesus gave a conditional statement regarding something that had no possibility of happening. It was used illustratively.
If I follow your reasoning regarding conditional statements, then I must necessarily believe that it is actually possible for a man to live a completely sinless life. After all, if one perfectly keeps the Law, one has no need for a Savior.
Conditional statements in and of themselves do not comment on a particular individual's ability/inability to meet the condition. They are simple statements of fact.
If my granddaughter is hungry I will feed her.
I know she will be hungry , that is no mystery.