You should check the other thread I linked, but I will make a tiny summary:
Nancy Reigle:
the Buddha when teaching his basic doctrine of anātman, no-self, only denied the abiding reality of the personal or empirical ātman, but not the universal or authentic ātman.
Bhante Sujato (criticizing the above):
When the suttas are saying the aggregates are not self, they are not saying, “These things, which we all know are empirical realities, are not-self”. They are saying: “These things, which you take in a metaphysical way as a self, are in fact conditioned empirical realities”. It becomes obvious that “consciousness is not self” is specifically referring to the Upanishadic doctrine (i.e. that of Yajnavalkya).
Thanissaro Bhikkhu:
when all experience of the six senses ceases, there is no thought, “I am” (DN 15). So, concepts of self and not-self don’t apply.