I believe tension tools came along for very light road-bike spokes and rims, and even then, many mechanics go by feel.
Adjusting by sound has worked for me with 4 e-bikes (including a Radrunner and a Radmission). I get the wheel off the ground and tap spokes with my spanner-style spoke wrench. The first time around, I tighten the dead-sounding ones and occasionally loosen one that sounds tauter than the rest. The second time around, I get them sounding pretty much the same.
A dead-sounding spoke could allow enough lateral movement to increase wear and affect handling. I've sometimes noticed improved handling after adjusting spokes on a new bike.