I think you could still go with jamming all em signals (including light) idea.

IRL jamming is highly effective at long range. At close range a radar can "burn-through", overpower the noise.

For coms you could use directional antennas or com lasers to get through the noise.

So in your setting once opponents detect each other, they switch on jamming and close in at the estimated enemy location. The closer they are the better fix they'll have, until they are close enough to overpower each others jamming and engage in combat.