I have many collars for my dogs. Flat buckle collar for tags(which they only wear when we are off property)
For my baby puppy, I really didn't use anything, he was naked most often when we trained. I wanted him to want to be with me, not because he was attached. Food, praise, then toys kept him engaged with me.
I went with a harness when he was about 3 months old when we went off property. I also had a heavier leather harness for protection work.
Around 6-8 months I introduced a prong. But I still used a fursaver on the dead ring only for many training exercises. I intro'd the e-collar at 3 yrs. We use that for certain things, but when he was trained on it, it was on him every time I trained, even if it wasn't used.
For my reactive dog, I used a gentle leader and a front clip harness because a prong ramped her up.
For my very handler sensitive dog, a flat buckle collar is all that is needed.
The only collar I've never used and never will is a slip chain choke. I'd rather use a prong than a choke collar.
For fosters, I use a martingale that cannot be slipped.