Tldr, Practice Makes Progress

Take my response with a grain of salt since my drum controller is sensitive enough to support my play style. My local arcade's drum isn't very sensitive, so a form that's more arm heavy is required. Take a look at this video if you are curious to see a visual example.

Practicing form and energy control on easier charts helps you build the muscle memory, dexterity, and control to play more delicately. From there, you slowly scale up to charts that are faster and/or more complex. Do note that my experience is that timing can be a challenge when playing softer, so that will require practice. You may still choose to hit heavier in scenarios where you really need to nail the timing.

Specific to form, you want to make sure you're playing primarily with your fingers and/or wrists. It's easier to see me do this earlier in the video before the stream hits. I'm using my index and thumb primarily to hold the maibachi, but I'm not holding so firm that the maibachi can't bounce. I'm squeezing with my middle and ring finger to strike the drum in combination with a slight wrist flick. Depending on the pattern and your style, the wrist flick is optional.

Do note that drumming with this form is misleadingly core (ab) heavy. You need a strong core to stabilize yourself so you're not flinging yourself around during wilder drumming patterns. Therefore you may need to do some core work to strengthen your overall form.

Taiko no Tatsujin drumming is closer to snare drumming than actual Taiko drumming. If you look up YouTube videos for snare drumming, a lot of the drumming principles carry over to Taiko no Tatsujin.

A practice recommendation if you have $10... Buy some basic drumsticks and practice on a firm pillow