Here are a couple of decent guides for reference, but the best answer is the pre-fit practice to determine your best Pad X/Y, which will allow you to review bikes & sizes based on that info.
For reference, I am 5’ 10" and ride a 56cm in most road bikes. I own the last rim brake Shiv Tri bike in size Medium. The Specialized size chart put me squarely in the Large size, but with research I found that they tend to recommend a size that is too big. Once I set my Med up, I found it perfect and was happy to ignore the Spesh info. Short point being that it takes more than quick research to confirm a TT/Tri bike size.