@Zarkun Ryder gave your character an order and she won't change her mind simply because your character demands it he answers to her not the other way around.
You have three choices right now.
1. Jericho can do as ordered.
2. Jericho can be grounded and SAM controls the ship.
3. Jericho can be killed off in the next attack. The Chaser destroyed.
Pick.
As for the Chaser if it wants to fly to and from the Nexus it has to be networked. A networked ship can be taken over by any sufficiently advanced intelligence capable of hacking can take it over given enough time. As for not having a SAM link neither does Remnant tech but SAM can interact with it.