"but something happened in 2017!"
Sorry but at the moment we do not know how much of an anomaly 2017 was. It was the first election since 1979 where the % for Lab+Con went *up*
The Liberal Democrats and the Tories had different leaders
We know more about Brexit now than we did in 2017
So if you tell me "but 2017!" you are, most probably, wrong. Or at the very least, not yet right.
/ends