The plot point is that you cannot be tracked while in hyperspace. Something the first order was able to do so they could follow them to their destination. Trackers are well established in the universe otherwise. They just only work outside of hyperspace.
Last Jedi:
Leia gives Rey a hand held tracking device and tells her that with it she will be able to find them wherever they go.
In THE SAME SCENE, they come out of Hyperspace followed by the First Order and claim it’s impossible to have followed them.
The tracking plot point is not mentioned again.
(p.s. A similar tracker was placed on board the Falcon in the OG Star Wars to lead the Death Star to the rebel base on Yavin 4).
The plot point is that you cannot be tracked while in hyperspace. Something the first order was able to do so they could follow them to their destination. Trackers are well established in the universe otherwise. They just only work outside of hyperspace.
That’s cheating, none of that movie made any sense whatsoever.