Hi FoxReinar,
I opened your FBX in 3Ds and took just the arm rest and baked out a Normal Map. I ditched the other geometry and only focused on the arm rest. I did increase the UV space for it to get a better bake as well.
Here are the results I’ve got. It’s still a little messy with the bake though just because I rushed a bit.
Here is a link to the asset I tweaked. I didn’t change anything with the geometry.
Ultimately, you may want to redo the topology for the low poly to get better results as this is where the issues appear to be.