Few PCIe slots available in modern PCs, does a PCIe extension chassis work?

[Saturn233207]

FIRST, the NEW QUESTION with preamble:

1. Our 6 new process control PCs have few card slots and PCIe are used for SSD and other things as super fast
2. We must replace all our 7 YO W7 production PCs as time, security and moving parts like cooling fans wear out
3. Our 6 new PCs, though I called for at least two, preferably adjacent, available PCIe slots in PC *Mfg RFQ what we got was OS C:/ SSD in one PCIe slot and a single port SUNIX RS232 COM Port (COM3) on the only remaining open PCIe slot.
4. Can pull that RS232 card out and replace but seems we might use a USB-C PCIe extension box
5. NI has used their custom board bus extension boxes for decades.  Latest is PXI etc.
6. Does NI have a simple low cost PCIe extension box for X series DAQ cards over USB-C?  Probably not as PXI is the new form factor for PCs that no longer have copious PCIe slots available.

NOW we see issues short Q:

Has anyone successfully used an external PCIe extension chassis, such as Star Tech and other Mfg offer, WITH USB-C (not Thunderbolt 3 as PC not Apple/MAC and TB3 proprietary to Apple) with DAQmx PCIe cards like X series DAQ PCIe-6323?  If so please comment on any issues and performance.  Laptops have zero card slots but newer ones USB-C.  I'm sure some of my developer fiends have done this before.  I do not see that NI has a USB-C PCIe extension box guaranteed compliant with their X series boards.  But if reading, NI engineers, please let me know if you do.  NI Blog supervisors, I know PXI is for this but we don't want to spend over $20 K now. Thank you very much for your responses.

Community Fiends:  Sorry about the larger font above but my eyes old and fuzzy.  Q must be made with no obvious errors. Many helpful answers found on this board, thank you all and I need to follow up with kudos for previous help.

Background: We have 20 NI PCIe-6323 X series DAQ cards, 2 per production PC and 8 or so PCI-8430/4, /8 and PCIe-8430/4, /8, /16 RS232 cards about for our numerous mass flow controllers.  We cannot use USB2 or 3 UART COM Ports for gas mass flow controllers as many toxic and is very bad to mix oxidizers and reducers improperly...  Well, we 'could' but would be incredibly unwise and I'm a Senior ChE in charge of these safety issues.  NO2, NO or O3 and Ethanol/H2/CH4/other fuels BOOM!!!  USB COM Ports can be anywhere as we know if jacks moved.  Best a fixed RS232 card on motherboard for toxic gas flows.  NI cards have a nice means of ALIAS and all other backup through NI-MAX if the database ever gets corrupted.  Fast and easy to restore system.  Kudos NI and NI-MAX!