Torpedoes are usually steered using fibre-optic wires, like the fibre-optic drones in Ukraine today, so there is no need for problematic low-frequency radio.
As funny as your comment sounds, I wouldn't rule out the Ukrainians actually doing it. At least for sea+air and air+air, sub-drones are already a reality.
This uses the same principle, but the traditional method required immense antennas and very high power radio transmitters.
Such antennas and transmitters cannot be installed in a small submarine.
Here a new kind of antenna is used, which is efficient under water even at small dimensions, so it can be installed in small submarines, for communication at distances of up to a few hundred meter.
The issue is it doesn't really matter and radio isn't much benefit: you get much higher bandwidth, better reliability, immunity to ECM, and fiber-optic wires in Ukraine are over 50km long.
The exact application for this is autonomous underwater vehicles where what you would like to do is communicate quickly and without a tether in arbitrary scenarios - i.e. think a bunch of autonomous vehicles which might need to relay a message or communicate with dropped assets. Using radio in those scenarios solves the problem of a consumable (the wire), and also the problems associated with sonar like fouling of the array.
fair enough but afaik torpedoes aren't tethered by a fiber optic cable like drones. it's a much thicker cable that possibly contains a fiber optic cable.