Since I'm now getting a 2025 vs a 2024 I got interested in the answer. A quick visit to the lexus pressroom says the minimum running ground clearance of the 2025 OT is 9.84" located at the under cover. I went to a parts catalog and it's located at the front suspension crossmember and the under cover is part number 51441 in this parts diagram. So, yes a 1" lift would provide an actual increase in ground clearance.
Not sure if it helps anyone, but it's too cold for me to go outside today and I'm bored.
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