Congratulations on having the opportunity to use a larger screen than a laptop or tablet. I use a 38" flat screen with my Kickr and it really does make the experience more immersive.
The base of the TV is on a table 39" from the floor, about 3" below the stem of my bike. The table is just in front of the front wheel of the bike. This works well for me. I suspect that some experimentation will be necessary depending on rider height.
Another observation that you may find useful; my ca. 2010 Sony Bravia TV sometimes does not show the the full image; see an earlier post of mine about this. To be sure that I see the full image, I make sure that the TV is connected to the laptop via HDMI before starting the Systm app and I don’t use full-screen mode (Windows icons are visible across the bottom of the screen). Of course, newer TVs may have more efficient communication with attached computers, so perhaps this won’t be an issue for you.