Safe offline Arduino IDE, maually install board library in platform IO

Dear forum.
Arduino IDE is to unsafe for using as it requires constant internet connection vacuuming for viruses, it also functioned as a backdoor to the windows update virus causing a bitlock error on one unit. I was adviced testing platform IO as platform IO might be able running offline once setup so here Iam. I have installed the portable platform IO IDE ver 1.85.2, it opens up and now Im trying to figure out how to manually download and install a board library/package. The platform IO IDE will never have internet access, that will not happen. I will download and sniff required packages manually because we need safe reliable computers. All viruses such as microsoft store, update, excel, onenote, bing etc is completely sanitized from all windows units at first boot. For this test I use a arduino r4 wifi which seem to require the renesas package renesas-ra 1.7.0 (link: PlatformIO Registry ).

Questions :

  1. Where do I find complete board packages/libraries for download ?
  2. When reading the platform IO quick start guide I get the idea I set the search paths to board libraries in the config file. After testing arduino ide, eclipse etc nothing is this simple so what did I miss here ?
  3. Please share advice and tips for running platform IO offline but skip your first advice “connect your platform IO IDE to internet”.

All ideas and tips appreciated.