Hi,
you didn't use setup guide to create the project (run "_create_win_setup.cmd" and use selection guide to create the project ), but this should be no matter.
I've tried it out on my place, at it works fine.
I've used: TE0820-test_board-vivado_2019.2-build_10_20200408073444.zip
--> also virtual drive J, generate design with "vivado_create_project_guimode" and device "TE0820-03-3BE21FA"
I've put my log to the attachment.
Only different is that you didn't install Vitis and you has Vivado version 19.2, I use 2019.2.1. I've put also a screenshot of the version part to the attachment.
On may place it open BD design before it loads block design from tcl.
Can you install Vitis, please (This is need for SW development like FSBL...., so you need it in any case)? --> Note: Vitis includes Vivado, so you must deinstall Vivado 2019.2 at first.
PS: XILINXGIT_DEVICETREE is not necessary, it's optional.
br
John