You don't need any expensive kit. All you need is a spoke key. You don't need a stand because you can do it on the bike using the brakes as a guide if you have rim brakes, oherwise a cable-tie or two make brilliant pointers. If you're truing a pre-built wheel, the only thing you need to do is figure out which way the rim needs to be pulled and where, then tighten the nipples of the spokes on the side you want to pull it to 1/4 turn at a time. keep going until the rim runs true.
I used a cheap Xact truing stand from chainreaction with good results. It clamps to a desk to give a good working height. Just takes time ans lots of little adjustments.
With myself, if I applied brake i would rock back and forth. Just no control over the braking pressure.
That's more likely to be a dent in the rim with rim brakes. Even if a wheel is out of true (a little) the brake caliper will just move sideways as the out of true part comes past the caliper. Disc brakes would prevent that issue in the first place. I personally wouldn't ride an Ebike with rim brakes unless they were hydraulic but that may be more to do with where I ride than anything else.
My wheels were slightly wonky from new, and they've been progressively becoming truer as my truing skills have been improving. Any time I do any maintenance (as rare as possible is my preference), such as when changing v-brake blocks, I true them a bit more.
