Maybe this is already solved, but I stumbled upon a similar problem.
My workPC has no direct internet access, so I wanted a complete portable installation, that I could move via USB stick or so.
I extracted the Arduino IDE ZipFile in D:\Arduino\arduino-Ide_2_0_3_Windows_64bit
Then start it once on an OnlinePC, load my libraries and Boards and then copied the downloaded/updated files to my USB drive:
Copy %USERPROFILE%\AppData\Local\Arduino15 D:\Arduino\UserAppdataLocalArduino15
For my Sketchbook I did the same:
Copy %USERPROFILE%\Documents\Arduino D:\Arduino\UserDocumentsArduino
In D:\Arduino\ I created a BatchFile mklinks.bat:
mklink /D /J %USERPROFILE%\AppData\Local\Arduino15 %CD%\UserAppdataLocalArduino15
mklink /D /J %USERPROFILE%\Documents\Arduino %CD%\UserDocumentsArduino
Then on a new PC I just need to call mklinks.bat and then I can start ArduinoIDE in my known envionment, can update Libraries on an online PC etc.
Maybe this helps you as well.