The Quad Cortext by Neural DSP is an incredible floor modelling device with more inputs and outputs than a swiss army knife. One of the reasons you bought the Quad Cortext might have been the potential and small form factor, as well as the promised ability to run the Neural DSP Archetype VST plugins natively.
Sadly, the Quad Cortex does not allow you to run your plugins on the device itself (yet), but Neural DSP is working on the functionality, and it will eventually come. Until it does, how can you use the plugins with your QC?
There are two approaches you can take as a temporary stopgap.
The Quad Cortex is a modeller as well as an audio interface. You can send the processed signal into your computer and the direct input (DI), which is unprocessed and the direct signal from your guitar.
Using a DAW like Reaper, you can create a track that uses the DI from the Quad Cortext. You then apply your Archetype plugin onto the track. It’s not the same as a native plugin on the Cortex itself, but it’s the same result.
Capture the Archetype plugin(s)
The flagship feature of the Quad Cortex is the ability to capture amps, pedals and a little known feature: capture VST plugins.
You can dial in your favourite Archetype sound, whether it’s Plini or Gojira, then capture the preset by routing the plugin through to your Quad Cortex and capturing it.
Admittedly, capturing is a lot more work, but the result will give you a sound capture that gives you that Archetype sound and without reamping or anything else.