P2422HE, Daisy chain troubleshoot, low resolution on 3rd monitor

In your testing, are both Laptops connected to their provided AC power bricks? The reason I ask is that the P2422HE USB Type-C upstream port only delivers 65 W "back" to the Laptops so if using "battery only", maybe an issue. I am also wondering if the Laptops cannot provide the USB-C bandwidth throughput to set all three P2422HE to Full HD 1920x1080 60Hz?

The P2422HE should have the private Service Tag on the rear label and in the Menu- Others. You enter that private Service Tag on that Contact Technical Support page =

@DELL-Chris M​,

I've tested both laptops with AC charging. Nothing changes:

I don't see why would the laptops be the problem. The G6X even supports DP 1.4 which should be an overkill for this scenario. Here's the serial number of the DP cables I use: "012dd-htn1-259".

I just don't see anything wrong.

I think The usual solution is to turn the USB data speed down, on the primary monitor. So the display traffic has priority

@Andy K​,

I don't think I have such option on this monitor. The one and only setting related to this is MST on/off option. However, I'd rather not lose the USB speed anyway.

I'd love to get an official statement from Dell, but the support page is impossible to bypass (even after entering service tag). See:

The USB-C Prioritization toggle is found only in the UltraSharp monitors.

Forget the site. Click the blue "Get Help Now" on the right to Chat with an agent.

@DELL-Chris M​,

Okay, that's more like it. So, after trying to bypass the support page and then chatting with a bot though "Get Help Now", I finally managed to chat with a Dell agent. Barely worth the effort, though. Actually I am still in this chat waiting for their latest statement. It's been four hours. They tried to convince me that my hardware is incompatible. Then tried to convince me that this is an expected issue. Basically everything to dodge the work on their side. Clearly incompetent/lazy staff. I had this expectation, and somehow I'm still disappointed.

That said, I may have found the answer myself. Of course, I cannot consider this screenshot an official Dell response, but it's something. So I may buy a cable from type C (laptop) to DP (1st monitor) to test this. It's really sad I have such a hard time to find a guy from Dell who knows how their monitors work, but that's that. Actually, I bet the chat support would use this/mine answer to... answer me.

You will still end up with 2 cables though. So no actual advantage.  

one for video and one for data. And charge hopefully

personally I would rather have the 3rd monitor as an additional cable. 

the advantage of the latest TB standard means one of the lanes can change direction to improve speed 

@Andy K​,

I'm not sure if I understand you. If this actually works, I'm supposed to have all 3 monitors up and running FHD with a single cable from the laptop to the first monitor. If you mean that I'd lose the USB-A ports on the monitor, then yes. But I still don't see another cable involved here. Or you meant that I can connect my laptop to the first monitor with two cables in order to keep the USB-A ports? I didn't even consider that as an option.

Yes. If you are plugging in a display port to the monitor, it’s not going to charge the laptop. 
And if you have an external keyboard and mouse etc. that will need a connection to laptop. 

@Andy K​,

Yes.

Maybe I will remain using daisy chain for two monitors and HDMI for the 3rd separately. What I actually wanted was an approval/disapproval from Dell about everything discussed, but I guess I'm never getting that.