Companion computer as GCS + radio telemetry to MissionPlanner

I am using a Pi on my drone that is connected by USB to the autopilot. The Pi runs mavproxy using master=/dev/ttyACM0 and has a two output links which are used in python scripts to 1,recieve attitude information, and 2, to input fake gps data.
In addition to this I want to use my radio telemetry, one connected to my laptop and one on my drone where the laptop using MissionPlanner will be like a GCS which sends/controls the mission, parameters, and recieves all telemetry data like usual.
I think somewhere I have a mismatch of connections because the radio connection was cut after a few seconds of flight and I no longer receieved data, then my plane crashed somewhere (where I havent found it yet) so I cant get the Pi to read its logs.
Does anyone have any knowledge on this? I think it is a problem in MissionPlanner that I haven’t set that there are more components. Or that one of the output links (like the one that just recieves attitude information) is being known also as a GCS so there is a conflict.
Any help/advice would be great.

So, if I understand this right, you were flying your plane with the telemetry link only, without a RC TX/RX backup, outdoors in an uncontrolled enviroment? I do not know where you were flying, but in most countries, this violates a lot of laws and regulations, not the least of which is common sense. Please tell me I am wrong.

I didn’t think that was necessary to add since it’s not part of the problem, but I have a GPS and a RC commander too for backup manual/stabilize control.
In my country, no.

I am very relieved to hear that. Why did you not use the RC and flew the plane back or switched it to RTL?

Because I realised too late.
Do you have suggestions for my questions?

Which law would it break? I dont know of any legilslation taht specifically details that you must use an RC link?