Mac Mini M1 Display Snow

Using my old Sony c. 2005 monitor, SDMHS95P, which worked fine on my last Mac Mini. With the new Mac, upon waking from sleep, the screen is 100% snow, like it's lost the connection. Turning the monitor off and back on brings back the desktop. Using the DVI out on the monitor, to a DVI-HDMI adapter on the Mac. I spent a bunch of time with Apple tech support, who suggested I empty caches (which worked briefly, maybe) and to start swapping parts (monitor, cables). If this is a "feature" and not a defect, I can live with it. Just don't want to let the Mini M1 warranty to run out if there's an internal hardware issue.