Please try to remember that a Kapex is not a fixed table saw.
The thing is for a Kapex to do its thing it needs a very flexible connection to dust extraction. Obviously during design research Festool found that a 36mm AS hose connecting a Kapex to their CT extractors provided all the suction needed. If they felt the need for a 50mm hose, they would have built the Kapex with the appropriate connector.
My own experience is that the Kapex works best with a CT when the 36mm AS hose is as short as possible. This is why I buy the 36mm x 7m AS hose with additional connectors, so from that I can cut off a 2.2m piece and still have enough 36mm hose to be useful with a cleaning set.
I also have found that the hose drags less on the Kapex when it is supported from above, as with a boom arm, or with a shock cord from above and behind the Kapex. This way while making the cut there is no drag on the Kapex.