In my current Dynamics 365 implementation, we are back in the On-Premise world, after many years.
We thought of using the Plugin-Trace logs but was surprised to see that the Plug-Trace logs were not getting generated.
After doing the search realized that it only works for the plugin registered in the Sandbox mode.
So for time being, we registered in it Sandbox to get the trace.
Found the below article that has the workaround (unsupported)
Meanwhile, we can also Vote for the Idea
Hope this helps..