I'm a gaming developer and I use Unity as well. To solve this problem, you can for example instantiate the dynamite with box collider disabled, however activate it only after 0.1f or 0.2f, I believe it should eliminate many problems.
An interesting way to solve this would be to create a layer for the player and another layer for other players, a third layer for the dynamite, then you go in the collision matrix deactivates the collisions of the dynamite with the player itself, leaving the other collisions active. Problem solved.
A hug and I'm looking forward to the new updates. Do you want to launch the game on Steam?