I’m not sure I fully understand your questions. Maybe you were using some kind of translation or AI tool.
Basically, from my limited understanding of UM982, it provides both position and heading, therefore I don’t see the need for another IMU sensor to determine the orientation. Unless you are dealing with some kind of tough terrain where the mower’s pitch and roll matters? I don’t know.
As per my experience with UM982, I stopped playing with it after the initial encounter of the problem described in the post. After switching to dual ZED-F9P, it has been working fine.
Not much improvement I can recall, not related to UM982, but I have swtiched from rtk2go to using MP as the RTK caster. Much more reliable for me.
On a different note, I might do some testing on UM982 again in my current project of converting Ego Z6 to Ardupilot, inspired by Martin’s project