No, they are definitely not non-slip, even if they are described as such.
I put a cardboard box of the right size between my wall and the pedals and made it a little heavier with books so that it stands securely. This works pretty well for me and the pedals don't slide around.
I hope I was able to help you a little

I can highly recommend a Playseat with it. I bought the folding one. It wobbles a bit and is not quite as stable as the other one, but it doesn't take up much space if you don't use it that often.
But something like this is definitely very cool for racing.
Or put a non-slip mat under it, something like under the carpets.

Otherwise, you won't be disappointed with the T300. Force feedback is really cool.
Have fun gaming.

I cut a board to size and placed the pedals on it. I then attached a strip to the front side, which stops the pedals from sliding. The board is then stopped by the wall. It's quick to make and holds even with heavy braking and heel & toe.