For particularly SFF (Small Form Factor) or thin client PCs, Thunderbolt 5 expansion alongside ... if you have an open PCIe ...

the race was on to be the first to connect a regular PCIe expansion card to a Raspberry Pi 4 SBC. Now [Zak Kemble] has created a new approach, using a bridge PCB that replaces the VL805 USB 3 ...

These new models allow for installing two QNAP QXP-T32P Thunderbolt™ 3 PCIe expansion cards (sold separately) to attain four Thunderbolt 3 ports for high-speed media editing and collaboration.