Fwiw you still run a risk that the CPU heatsink or something similar will come dislodged during shipping, and tumble around inside like a wrecking ball, smashing up the CPU, 3080 and the other parts you want to keep.

I learned this the hard way. There's a difference between how computers like Dells that are designed for mail order are made, vs modular DIY ones. The interior parts of the former are more strongly locked down inside. They're more likely to be non-standard and difficult or impossible to upgrade, but that's the cost of making them UPS-proof (United Package Smashers).