Once it's broken in the need for additives is less important. Too much of some types of oil additives, like zddp, can supposedly lead to the metal corrosion as it alters the oil composition.

Bob is the Oil Guy is a good site to read up on different types of oil and additives. Some real chemist geeks on there that deep dive into things way over the average person's head.

Found this too while reading about camshafts and oil.

https://www.nonlintec.com/sprite/oil_myths.pdf