RigidBody.velocity or transform.position

Hello,
I have a game with Turrets. As they shoot, they produce many projectiles (probably thousands). Every projectile has a script on it, which moves the projectile using

transform.position += transform.forward * speed * Time.deltaTime;

in the Update method. I thought about using RigidBody force instead, as the projectiles have attached rigidbodies anyway. When I use force, I only have to set the rigidBody velocity in the Start() method.

I don’t know, whether I should use the physics movement using rigidBody.velocity or transform.position.

Which one is better in performance with hundreds/thousands of gameObjects?

I also thought about merging projectiles into one gameObject and creating meshes, but because of the projectile Inaccuracy and deviation this would be very hard.

Use velocity please. There are a lot of reasons why.