I-Boats did play a role!
But a few factors are at play. Japanese subs could be absolute monsters. They built the largest pre nuclear power submarines of anyone. And their boats had impressive range and endurance for the planned war in the Pacific, while also being damn fast in the water. And of course the famed I-400 class of boats that could carry small aircraft(the IJN had a gaggle of smaller similar designs too). And were armed with very modern torpedoes. But their boats werent very maneuverable, didnt carry any radar till late in the war, and were more fragile than peer designs.
There just werent many of them. The IJN started with 63 true ocean going boats, and built 111 more. For a total of 174 hulls. They lost 128 of them. With most of the surviving ones having been in training roles or completed late in the war and seen little if any real use. Nazi Germany meanwhile completed over 1100 U-Boats!
Doctrine. The IJN wasnt interested in striking at merchant shipping or using subs against sea lines of communication to strangle its foes. The sub force was to be used against enemy naval forces, ideally in conjunction with air and surface forces. The plan for Midway for instance involved attacking the island, then the USN forces that came out would sail into a picket line of I-Boats waiting for them. As the war progressed too, many boats were used as blockade runners, bringing a trickle of supplies to isolated island garrisons. Though as Allied ASW improved many also had remarkably unproductive patrols, indicating morale had plummeted to the point that crews were simply trying to survive, and not seeking out sightings or contacts very aggressively.
There were a few cases where their presence was felt. Notably to start the war, 30 subs were involved in the attack on Pearl Harbor. Some as motherships to midget subs, others strung out around the islands, and back to California, hoping to catch targets. These boats hit a few targets and even shelled an oil refinery in Southern California, creating a panic in early 1942, as parodied in the movie 1942. While the ones around Hawaii played cat and mouse with the surviving US carriers, putting a fish into the Saratoga in January, sidelining her for a few months. Then in June 1942 I-168 finished off the damaged Yorktown the day after Midway. While that Fall around Guadalcanal, the I-Boats were in their element. USN task forces were ordered to operate in relatively confined areas to cover convoys and the approaches to the island. I-26 put a fish into Saratoga again and sent her back to Pearl in late August. September 15th then brought us what may be the single most effective spread of torpedoes ever fired. I-19, with 6 torpedoes, 3 hit and sank the carrier Wasp, one hit the destroyer O'Brien which would sink on its way back for repair, while another continued on and hit the 5NM distant battleship North Carolina which would spend the next 2 months in the yards for repair.
But while effective in the moment, the efforts of the IJN's sub force were not enough to change any of the strategic calculus. Nor were there ever enough of them to apply the sort of pressure that came from the U-Boat force.