Review on 📶 5G M.2 Key B to Mini PCI-E Adapter with Dual Nano SIM Card Slot for 3G/4G/5G Module – Timack by Daniel Casper

According to the one star reviewer, most 4G and 5G modems work over USB. The EM919X series runs over PCIe, but to be honest, that's Sierra Wireless' fault, not the adapter's. There are hardware modifications you can make to the EM9190 to make it boot from USB, which again Sierra Wireless should have done right away. limited to less than 480 Mbps when overhead is included. I don't know of many carriers that can hit those 5g speeds yet, but if you really want to protect your setup in the future, I would buy a USB 3.0 adapter.