I’ve done this before and it works Ok.
Here are a few observations…
Yes, sometimes some types of plywood warp a bit. If you fiddle with the time and temperature you’re using in the heat press you can reduce that. I also weigh down the plywood until it cools, which also helps a bit.
The resulting ink on the plywood transfers much better if the plywood is very smooth. I give it a quick fine sanding, clean off the dust, and it’s good to go.
The colors will be muted since it’s being transferred to a non-white base surface. Someone recommended that I apply a paint white wash to the plywood first, but I haven’t tried that yet.
Also, the sublimation ink WILL come off if rubbed with isopropyl alcohol, which I learned while removing soot marks. I can just mask the wood instead to eliminate soot issues.
Here’s a photo of an untreated sublimated plywood experiment I tried recently. Go ALL the way to the bottom of my post to see it (aka “Fancy Plywood 3.0”