Round rice or “pudding” rice is essential, it’s a short grain rice that releases a lot of starch. If you can’t find it then sushi rice can be a useful substitute. As you found the risotto rices don’t release as much starch - the reason why a good risotto retains the definition of the grains.
I have not been back to CLJ for years - we used to eat their frequently about 12 years ago when it was simpler and less of a tourist trap. On our last visit about 4 years ago I thought the rice pudding had lost something and all the accompaniments overwhelmed it’s simplicity.
I have got pretty close to recreating it but it’s quite rich and most recipes make enormous amounts. Maybe time for a reprise.
