My second monitor daisy-chained to my Dell u4025Q does not switch with built-in KVM

I have two computers : 1 PC running on Windows 11 and one Mac Studio Ultra M2.

The PC is plugged to my main monitor, the Dell u4025qw via DP

The Mac is plugged to my main monitor, the Dell u4025qw via TBT4

My peripherals (mouse, Keyboard and webcam) are plugged to the u4025qw and work fine on both computers via the built-in KVM.

I have a second monitor (Benq SW271) daisy chained to the Dell u4025qw monitor via a TBT 4 cable. The cable is plugged to the right TBT 4 port on the dell monitor (that is the one made for daisy chaining), and to the USBC port of the Benq monitor.

The Benq monitor works as intended as an extended display with the Mac Studio, but does not switch to PC when I change to DP as input source on the Dell monitor (ie - KVM does not switch the second monitor to PC/DP and displays the Mac/TBT 4 image no matter what).

What should I change to my set up for the second monitor to switch to PC together with my main u4025qw monitor?

Many thanks!