I may need to go through the whole list and mark more of them as unavailable, but in theory the ones under "Mass Produced" should be available fairly quickly from a large enough retailer that your employer would be willing to buy them.

The ones under "Assembled" are from small businesses or side businesses, or at times may be unavailable for months, or have week+ delays before delivery. There are some companies like https://falba.tech/ (EU) and https://bastardkb.com/ (Canada?) who make several models.

https://www.reddit.com/r/ErgoMechKeyboards/ is the best place to ask if you have other questions, including on other suppliers.

The UHK and the ErgoDox are the two most prominent preassembled ones. The former is out of stock, though.