Hi,
for long time I'm searching for a silence clip in my media-bin for using it together with black or white color clips in transitions.
(fade to black or white and back again...)
I'm going now to use an external (real) clip, but thats not very handy, I think.
I know, one may use fade out - fade in (audio), but this is much more work per fading (if there are some hundreds of them).

How do you handle such cases?
Have overlooked something?

Why don't you take an audio file, apply a volume effect and bring it to -100db. Adjust the length to what you think would be the longest silence period you would ever need in your project. Then add this clip to the library and call it 'silence'.
Then you can bring this clip into your projects as often as you need and simply adjust its length in the timeline.

Yeah, that's exactly what I'm doing now
But, I'm a lazy guy & my old Premiere has had such a (long loved) thing...