I have exactly the same problem. Got this problem after updating to latest windows (1909) and latest opera. Opera just randomly close itself after being opened about minute and there is no error. I also have ryzen processor maybe that is the cause. On my laptop with Intel processor everything is working fine.

However opera GX is working without any problem. The same applies to Opera 67 that I have downgraded to. So I guess I'm not the only one with this problem.

Hope they will fix it soon.