McBain
Player Valuation: £80m
It was explained that the Avengers travelling through time didn't create new strand because that was what was "supposed" to happen, and was part of the "sacred timeline". Loki however wasn't supposed to pick up the Tesseract, and THAT is what caused a branch/nexus event. They didn't reset it immediately because they needed Loki to help find Loki/Sylvie who they so far hadn't been able to find/stop.
Why? They should have reset the timeline once they got Loki, and they knew exactly where Sylvie would be after all the times she apparently knew where they were going to be and murdered them.