Spare ribs was the second thing that I learned to make in the Instant Pot.
The first thing that I made was a 4 pound pork shoulder and it was absolutely delicious and I repeated that a few times. I had watched several videos showing people making spare ribs and I finally decided to make them.
Since then I have made them countless times and we (as in my husband and I) are now adjusting the pressure cooker time to get them cooked to the point that they are done and tender but stay on the bone enough to transfer them to the grill without them just falling off the bone.
Just a quick point about adjusting time when using the Instant Pot. I first was adjusting the time in 10 minute or more increments. That does not work very well and I've had a few times where the ribs were not done. Since then our adjustments have been in one to 2 minute increments. We are getting it just about right with 2 racks of ribs. this time can change if you are getting baby back ribs or Louisiana style ribs or just standard trimmed spare ribs. Time will also be different if you are cutting the ribs apart individually or cooking them in slabs.