Issue with Mac Mini M1 and Dell ultrawide display

I have a 2020 Mac Mini M1. A few months ago I bought a Dell S3422DWG 34" ultrawide monitor. This is connected via the HDMI output to the monitor's HDMI input (note: even though the Mac has a USB-C/Thunderbolt output compatible with DisplayPort, and the monitor has DisplayPort input, I simply cannot get this to work; perhaps this is related to my issue).

The issue I have is that when the monitor/computer are awakened from sleep mode or turned on, about 90% of the time the screen has a "cross-hatched" appearance. This is the best way I can describe it, but I'll attach a pic if this forum allows it. I believe this has happened from day 1 with this setup. I remedy this by simply turning the monitor's power off and back on. I usually only have to do this once ... or twice ... and the display is then fine. I was able to live with it. Problem is that over time I sometimes have had to do this 5, 6 or more times. A few days ago I had to cycle the monitor's power more than 10 times to fix the display.

Decided to contact Dell. After 30 minutes of tech support, the conclusion was that Dell just doesn't support this monitor with Macs; they only make drivers for Windows. They advised me to contact Apple. I'm wondering if anyone here has advice.

Of note, I also have a mini-PC running Windows 11 hooked to this same monitor via the DisplayPort, and I've never seen this issue with the Windows PC. I've also swapped out the HDMI cable to the Mac at least once, just in case that was the issue.

It's just very annoying. Let me know if it would be helpful to post my Mac's specs.