Ultra Wide Monitors Woes Woes With Mac mini M1?

[Stephen Bond]

Hello one and all,
I recently bought a Mac mini M1 and am loving it. Power, speed and tranquility

The only issue has been running an ultra wide display. Obviously tempted by the thought of running a gazillion channels and seeing them all on screen at the same time with a humungous arrangement I took the plunge.

First purchase LG 29UM69G 29 inch 1ms 75Hz Ultrawide IPS Gaming Monitor (2560 x 1080, HDMI, DisplayPort, 250 cd/m2, AMD Freesync)

Nice enough monitor. However, I noticed the screen going blank for 1 second and a touch of white noise on occasion. I tried different options in System Preferences/Displays beyond the default (not that there are many) and no change. I swapped monitors with my son who has a Dell S2319H to test and got him to use the LG with his X Box. Fine on both accounts.

Anyhow, I got tired of the issue so assumed it was an incompatibility and went to purchase my own flavour of Dell.

Second purchase
Dell S3422DW 34 inch WQHD (3440x1440) 21:9 1800R Curved Monitor, 100Hz, VA, 4ms, AMD Radeon FreeSync, Built-in Speakers, DisplayPort, 2x HDMI, 3x USB, 3 Year Warranty

Plenty of real estate here, increased resolution and away we go. Sadly, my initial "I've cracked it" turned to despair as I find this has the same issue. Blank screen at random times for around a second.

I have also used three different HDMI cables with the monitors so we should be able to rule that out as the culprit?

So anyone got experience with this? Is getting a UW working with the Mac mini M1 tricky or have I just been unlucky? If so, what monitors work and what spec should I look for? Otherwise, is it just a software configuration thing I am missing?

Many thanks in advance!

Stephen