I just make a huge pot of oats - 24 oz dry steel cut oats - at once, and then reheat in the microwave. It usually lasts about a week +/- depending on my ride schedule.
I usually make it with just water, or sometimes I mix in beaten eggs while cooking to add extra nutrients and give it a creamier texture.
I just do high pressure for 20 minutes and natural pressure release. I also like to rinse and soak my steel cut oats so that may affect cooking time if you don’t. If I end up with some extra liquid, I just laddle it out before stiring. If you use too little water in the Instant Pot you’ll get the burn message though it will still cook.