You could also imagine the converse, where someone from the future brings back all scientific knowledge, thus reducing the time it takes scientists of the past

You could also imagine the converse, where someone from the future brings back all scientific knowledge, thus reducing the time it takes scientists of the past to invent time travel, which in turn leads to that person bringing back all scientific knowledge sooner, perpetuating onwards until massive amounts of knowledge are acquired in small amounts of time. Such is the nature of the grandfather paradox.