Ok, take this with a grain of salt....as I have not used mine for Pizza on the grill just yet (and it will be for Kamado, not Pellet)...but I went with Steel vs. Stone.
Found it online...1/4"-3/8" seasoned steel plate. After a lot of research (seriously, I typically overthink about everything I buy)...came to the conclusion I would like the steel better. Gets super hot, can use for multiple applications (Pizza, smash burgers, seafood, eggs, pancakes...) And it reviewed well vs. stone.
Im pretty sure this is what I have...
They have 1/2" and 1/4" as well...the downside...the weight.
Ordered it as the "Baking Steel" was not out for the round the size I wanted for the Kamado. There are a bunch out there for a rectangular shape that wouldn't work for me.
https://slice.seriouseats.com/2012/09/the-pizza-lab-the-baking-steel-delivers.html