Thanks for the info. Here’s my setup and it’s different than yours, but I learned a few things here that you might want to consider.
First off, I use a Logidoc breakout box (that connects to the Laptop with a USB C connection) with 1 HDMI output and 1 DP output. (Remember that the laptop has 1 HDMI output on it and I didn’t use it.) My laptop is a 3 year old ASUS TUF 15 Gaming Laptop, running latest Win11, Intel i7 -11800H, 8 Core, 16 G ram, along with an Nvidia Ge Force RTX 4050 video card. (Note: the display screen on the Laptop boasted a refresh rate of 144hz, my desktop Dells are 60hz).
Here’s my experience. At first I connected two desktop Dell displays to the Logidoc, one connected vis HDMI, the other via DP. I did not use the laptop display although it duplicated one of the displays, whichever display I setup as the main one. This worked for about 1 year, although the DP display had some strange random sparkling snow, faint but always there. I swapped monitors and the snow followed the DP connection. Then one day there was a flickering of the DP monitor, sometimes turning off but then restarting on reboot. However eventually it turned off completely. The Logidoc was up to date.
Here’s where things get interesting. The onboard Intel video card had been asking for a driver update - but I had been avoiding it because I was (I thought?) using the GeForce video card. Why would I need to update it? But… I decided to update the Intel card… and nothing changed. I also updated my GeForce driver the next day as a new driver had been released. Nothing changed. Windows could not find the 2nd desktop display after many attempts. So, I decided to get a bit radical in my attempts to sort the problem. It had occurred to me that perhaps the Logidoc was a fail, and, after a phone call, Logitech sent me a new one, gratis. I installed it but nothing changed. At this point, following my radical leanings, I thought that perhaps a Windows Update had caused the problem? As I thought about things, I considered that if I DISABLED the Intel graphics card, and therefore the laptop was dealing with ONLY the GeForce card, things might sort themselves. So I DISABLED the Intel card. And before somebody starts saying that this was a very radical move, a mistake, know that this is exactly what I have done to my Desktop PC where I’ve run 2 monitors on an AMD Radeon Pro card without a hitch for years. However this did not bring back the 2nd desktop monitor - and - I now had the laptop and 1 monitor showing the same display. I opened the Nvidia graphics app and it confirmed what the Windows Display app showed. The 2nd monitor was invisible. I stepped away and went to bed.
The Intel video card. The HDMI output port on the Laptop.
When I woke up in the night 2 things occured to me. I should ENABLE the Intel graphics card, and then use the HDMI output on the laptop for the 2nd monitor. I made these changes and opened the Windows Display app. It shows only 2 monitors, labeled (1/3) - 2. Here, the Laptop shows the number 1/3 on the laptop and on the #1 Dell monitor and the #2 on the 2nd Dell monitor.
I know this is a long read, sorry. Q: Do you think there is any way to NOT make the laptop the MAIN display? I don’t think this is possible. The 2nd monitor can either mirror the Laptop or it can be made an extension of the Laptop screen - and I’m sure that’s what you’ve setup with your system.
BUT - looking at the Device Manager right now and my setup, here’s what I see in regards to the two desktop monitors and the Laptop monitor: the Laptop monitor is controlled by the Intel video card along with monitor #1 (fed from the USB C out of the Laptop into the Logidoc and out the Logidoc’s HDMI), hence the ‘1/3’ label which is plainly confirmed by the Device Manager - and - Monitor 2 is controlled by the Nvidia Geforce card fed from the HDMI port on the Laptop. If I open the Nvidia app, it shows only 1 monitor, not 2, not 3, and this is the #2 Dell monitor.
I’m sure this is a complicated read, sorry again, but I’m suggesting that your laptop screen is controlled by the video card installed on your MB, and your 2nd monitor is being controlled by your Nvidia card. Which is to say that there is probably something about the Nvidia card that is causing your problems. Not what you wanted to hear, but take a look in your Device Manager and confirm what drivers (Intel or Nvidia) are attached to your laptop monitor and your #2 monitor. Then open the Windows Display app and ‘identify’ your monitors, (s/b 1- 2), and then open your Nvidia app to see if it shows one or two monitors. Get back to me.