I presume you are using the VGA and two DP from integrated video at back IO of 7010.

Yes using the integrated inputs.

do you get both DP monitor working if you do not have the VGA connected? 

At most the system only lets me use 2 monitors. Singly or in any combination. 

Do you have each DP monitor working individually when you connect VGA and just one DP monitor?

Currently I have both DP monitors working. I can run one on the VGA and one on the DP. Just not all three at the same time.

based on your report, are you saying when you plug in one VGA and one DP, then plug in the second DP, the second DP gets no video?

If I plug in the VGA and a DP, both will work. When I plug in the other DP then the VGA turns off and the two DP will be left working.

  and same story if you plug in both DP, then plug in VGA, the VGA gets no video?

Yes. System only recognizes two monitors. Won't allow the 3rd to work.

in my experience sometimes the system takes a while to adjust to additional monitor.  a hot plug in while system is on also behaves differently from a cold plug in (meaning all 3 monitors connected during power off then you power on pc).  what happens if you do a cold plug in of all 3 monitors then turn on pc.  after Windows 10 is loaded, which monitor gets video?

I've rebooted with all 3 monitors plugged in. I will try to do a shutdown with all three plugged in to see what that does later. It's a really strange issue. I know that it worked before I reinstalled the OS. I'm just missing something here to get it working again.

Re: When I plug in the other DP then the VGA turns off and the two DP will be left working.

Did you do a fresh clean install of Windows 10 on the pc before the monitor issue?  did the issue arise immediately after the reinstall or a bit later?  it seems there is a conflict of motherboard video port drivers that when both DP ports detect monitor, it disables video to the VGA port.

if install is clean and issue immediately occurred after reinstall, then a second clean install would not help.  if otherwise try a second clean install by wiping hdd and see what happens.  are you using 21H1 the latest version?  does Win 10 automatically download the appropriate HD4000 driver for the chipset after reinstall (try not to manually download video driver from Dell at this point)?

try clear cmos by resetting cmos jumper on motherboard and replace cmos battery with a brand new one just in case something is strange of the BIOS. 

I presume you are using the VGA and two DP from integrated video at back IO of 7010.

do you get both DP monitor working if you do not have the VGA connected?  Do you have each DP monitor working individually when you connect VGA and just one DP monitor?

based on your report, are you saying when you plug in one VGA and one DP, then plug in the second DP, the second DP gets no video?  and same story if you plug in both DP, then plug in VGA, the VGA gets no video?

in my experience sometimes the system takes a while to adjust to additional monitor.  a hot plug in while system is on also behaves differently from a cold plug in (meaning all 3 monitors connected during power off then you power on pc).  what happens if you do a cold plug in of all 3 monitors then turn on pc.  after Windows 10 is loaded, which monitor gets video?

The 3 monitors worked before the fresh install. After the fresh install the 3 monitors won't work at the same time. Limit of 2 monitors.  And yes latest version. 10.0.19043 Build 19043.

Issue occurred with the stock drivers, issue persisted after downloading of the drivers from windows update. Issue persisted after downloading the latest drivers and bios as well. 

I don't think that I'm up to re installing windows a third time. I may just get a video card and install it on here to get the 3 monitors at this point. Feeling it would be faster.

that is a good plan.  still can not explain why all of a sudden the pc loses VGA when both DP plugged in, but since this is an older model, will leave it as an unsolved mystery for now.

I was able to fix the issue without installing a new Graphics Card. In the device manager, I updated the drivers for my dell monitors so they also showed the same as yours (2 DisplayPort, and 1 Analog). Next, I uninstalled the video card, but I did not uninstall the drivers. After the graphics card was uninstalled I was prompted to restart the machine, I said No to restarting. The device manager then only showed 1 monitor instead of 3. I went to uninstall the last monitor and said no to uninstalling the driver for the monitor. After doing this, the graphics card reinstalled itself, then a few seconds later I had all three monitors in the device manager showing again. I had still not restarted the machine. I then right-clicked the desktop, went to GRAPHICS OPTIONS --> OUTPUT TO --> and selected EXTEND DESKTOP 3. This immediately triggered all 3 monitors to work in unison as extending the desktop.

I get this menu but it won't show me 3 desktops, it only shows that i can clone/extend it on 2. also sorry for sending a year late