If you know where it is once it’s easier to keep track of it ships can’t teleport which substantially limits the search space. Then your limit is related to bandwidth but that seems to be a case for edge compute. And I assume there are a ton of sensors that could be tailor made for the purpose, wouldn’t radar be effective?, a low resolution IR?. And there is the ability to use other sources of intelligence in conjunction. And what’s to stop adversaries building a bunch of neutrino detectors which nuclear reactions cannot hide from, currently they’re slow to detect but it’s probably easier to fix that by building a ton of them. I suspect above ground neutrino detection technology is now good enough that stealth and nuclear are no longer compatible, and that includes nuclear powered submarines.