@Dinmiller  Make sure MST is enabled on the first display in the chain. Also make sure you’re using a DP to DP cable to connect to the second display, not DP to HDMI or DP to USB-C or something.

MST is enabled, and it was a DP to DP cable. sorry forgot to mention that.

@Dinmiller  Just to isolate variables, does the second display work when you connect that DP to DP cable directly to the DP output of your desktop? Are you sure you’re using the DP output on the U2422HE and the DP input on whatever other unspecified display you’re trying to use? Incidentally what is that second display? Are you sure you have enough bandwidth on the daisy chain to run it?

@Dinmiller  If the USB-C link is also set up to support USB 3.x data rather than just USB 2.0, then video bandwidth on USB-C will be half of what is available when using the DP input.  I believe the U2422HE configures the link for USB 3.x without offering an option to limit speeds to 2.0 to maximize bandwidth (though some of Dell's 1440p displays offer that customization).  However, even if your laptop only supports DisplayPort HBR2 rather than HBR3 (fyi it might have been wise to provide your laptop model too), there would be enough bandwidth for dual 1080p + USB 3.x.

I haven't used that exact combination of displays, but I've set up dual 1080p daisy chains with Dell USB-C displays as the first display in the chain before, and helped many others do the same.  If MST is enabled and you're absolutely certain you're not mixing up DP outputs and inputs on these two displays -- which I've seen people do multiple times! -- I'm not sure what to tell you.  Does Windows Display Settings even detect the presence of the second display even if it's not sending a signal to it?  Are you trying to run any other displays from this laptop?  And just in case it matters, what exact laptop model are you using?  (Fyi when asking for technical assistance, it's generally worth providing basic technical info such as the models of all equipment involved upfront.)

its a latitude 5510, up at work they had a type c dock for it with 3 DP ports coming off the dock to 3 P2419H monitors so i know the type c is capable of pushing it.  the monitor is only showing a link of HBR2 tho with the type c connected to it so im not sure why. (yes it is the same laptop i was using up there)

@Dinmiller  The Latitude 5510 uses Core 10th Gen "Comet Lake" CPUs, which only support DisplayPort HBR2.  Only the Core 10th Gen "Ice Lake" CPUs supported HBR3.  I'd be curious which dock you were running.  It's possible that you had a dock that used "indirect display" technology such as DisplayLink -- not to be confused with DisplayPort.  The Dell D6000 and a variety of other "universal docks" use that.  And that does allow higher-end display setups to be run because that tech basically involves converting video to regular USB data and then compressing it as opposed to using a native GPU signal, but as you might expect, DisplayLink's compression introduces its fair share of drawbacks as well.  Still, like I said, even an HBR2 system can run dual 1080p (using a native GPU signal) and USB 3.x simultaneously, so if you've successfully tested the DP cable and DP input of the P2419H using a direct connection to your desktop and have made sure your daisy chain cabling is correct, I'm really not sure what to tell you, other than maybe uninstalling and reinstalling your GPU drivers?

After many unplugs and replugs, turning mst off and on multiple times... it all finally started working. No clue what the issue was but its working perfectly now.