I would recommend contacting your local "Craters & Freighters" :: https://www.cratersandfreighters.com/. They are a franchise nationwide, specializing in the build of custom crates for basically anything electronic. I've shipped millions of dollars of equipment with them over the years, and not a piece has been damaged. Custom foam, custom crate, and they deal with the customs paperwork too, so it's very much worth the expense, in my opinion... at least for something the value of the 8K.

And speaking of expense, two crates that size plus shipping will probably run you about $1.5k-2k. You might be able to DIY cheaper, but not a ton, and not with insurance.

Main System: MiniDSP SHD (Roon, Dirac, Volume) > G61R > DSP5200 Speakerlink L/R, 2x SVS SB3000 Subwoofers
Office1 System: Genelec 8030c L/R, Genelec 7060B Subwoofer
Bedroom System: DIY Sure 2x100w Class D Amp, ELAC DBR62 L/R