U2421E, U2415, daisy chain, U2415 inconsistent

I have a Dell 2421E daisy chained to a Dell 2415 monitor. The two monitors are connected using DP to DP and the 2421E has a USB-C out connection.

I had an old Dell XPS 15 running Windows 10 which worked fine with both monitors and work provides a Lenovo running Windows 11 which works fine with this set up. Just plug in the USB and go. (I needed extra power for the XPS 14)

I have upgraded to an XPS 14 9440 running Windows 11. Every time I plug in the 2415 drops to a Wired generic monitor running 1920x1080 resolution instead of 1920x1200. I have to unplug the cables to fix it. The Lenovo doesn't have this issue and my old Dell didn't which implies it isn't a cable issue.

Dell Display Manager cannot see the 2415. I can fix it by not daisy chaining and using a DP to USB-C cable into the XPS but that is sub optimal as I only have limited USB slots and hot swapping between work and personal laptop is a bit more fiddly.

Any idea?