Help needed! Lost external displays

Hello, i really need some help. I have a Late 2015 27inch iMac running Monterey 12.7.4. I am an absolute novice to most computer things and definitely OpenCore but being stubborn I have been trying to find a way to use this iMac as a monitor for my MacBook Pro. I found this YouTube link https://www.youtube.com/watch?v=sO0yc3_hOE8 and thought fantastic! I'll try it. So I used the latest patch showing in the link provided in the video and followed the videos instructions of creating the boot drive and running the program by choosing to boot to that drive and YAY! it worked. There was airplay and I could connect to it. I didn't have a lot of time, so I just put my laptop away and went back to using my 2015 iMac with two external displays as I always have — I did not boot out of OpenCore—and 24 hours later in mid-use <poof> no more external displays. I cannot get the iMac to recoginize the two external displays that I have been running on this system for the last 5 years. The opencore patcher must have changed something. I tried rebooting without the OpenCore patcher boot disk, as the video stated that would put my Mac back the way that it was before ever using OpenCore but nope. Airplay is now not showing but still no external displays. Pushing the option key in the display settings does not make Night Shift switch to Detect Displays so something is clearly wrong. I am panicking. I use this mac for work every day. I have zero idea how to troubleshoot this or what to do. Of course I did not make a Time Machine backup. Can I get it back to how it was before OpenCore? Can anyone help me figure out how to troubleshoot this and hopefully walk me through getting my displays back? I wont be able to really work on this until tomorrow though, I am in the US Eastern time zone. I really really really would appreciate any help. I am so lost.

submitted by /u/KathCobb
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