The 1:1 is the proportion recommended for rice, even brown, by the Instant Pot, since it is totally sealed, and loses very little water, compared to cooking on the stovetop. Usually much more water is suggested for brown, since it cooks longer, thus loses more water.On a related note. Your recipe for stovetop rice is way off in its proportions of water and rice. I recommend you try adding one cup of rice to 1½ cups of boiling liquid (water or broth). Tests have shown that each cup of rice absorbs one cup of liquid. Adding a half cup extra provides for evaporation.
I did something today that made me think of this thread - I cooked some barley in advance, to add to a dish tomorrow, which is not jambalaya, but similar, and it reminded of when I had made jambalaya with barley, and another time with oat groats. I did this for some friends who were diabetic, and these are better grains than rice for them, esp. white rice. The oats looked like a shorter rice, the barley not at all like rice, but everyone loved them, when I made them.