Eren ended up affecting the current timeline in more ways than one with his groundbreaking moves.
By curing Arizihana of the side effects of using the spiked potion, he first prevented her death. Eventually, he ended up hiring her. Arizihana had served as a very popular city protector for the city despite her relatively low-ranking status. Her absence and the absence of her iconic image prompted the city of Silvermoon to bolster its defenses.
The butcher also destroyed the Beast Bloods' hideout and weakened its influence in the region close to the city of Silvermoon. He then ended up creating a tussle between the Beast Bloods and the Illuminati after his exit from Purgatory. That affected the Beast Bloods' ability to have designs on the city of Silvermoon.