I'm sorry!
The content of your desktop file suggested me the SNAP or other kind of installation.

Few unnecessary indications:
After you extract the SweetHome3D-7.1-linux-x64.tgz,
inside the folder SweetHome3D-7.1 you will have two bash files:
SweetHome3D and SweetHome3D-Java3D-1_5_2. To one of this have to point the Exec= statement from desktop file.
All your huge entry it is inside of this files and this is necessary for program to run.
My SweetHome3D-nimbus it is a customized file to use Nimbus Look and Fill.
Also, in my installation, I use an extra folder, to store multiple variants of SH3D and the editors, named Sweet_Home_3D.