This problem has been driving me slightly mad over the past few weeks, and I finally found a fix.
I've been using a lenovo Thunderbolt 4 Dock Docking station (40B00135US) and I have two monitors hooked up to the dock as external displays. One with display port, and the other with a display port to hdmi cable to connect a monitor that only had hdmi.
The issue I was having, is that any time the displays went to sleep, when you would wake the laptop again, only the laptop screen would turn on, and the two external displays would stay off. I could "reset" them by using arandr and moving one of the displays, clicking apply, and the displays would turn on, and then you could move the monitor back into the correct layout and apply and be working again. But this is obviously insanely annoying. I tried disabling dpms, did some firmware upgrade on the dock itself, firmware upgrades on the laptop, and nothing made any difference.
Finally I ended up swapping out the hdmi monitor with a different monitor, and it would still do the same thing on hdmi. But after changing out the DP to HDMI cable for a DP to DP and running both monitors on display port now, the issue has gone away.
So not a great solution, had to change out monitors, but at least it's working now.