If qualifying as a technical civilization can be defined as being able to launch a self-replicating interstellar probe (a/k/a a Bracewell-von Neumann probe), we can be confident that our galaxy has not yet had one. Once those probes are out there, they'll saturate the galaxy permanently; and once a technical civilization can launch one, it'll happen eventually. A modern billionaire could probably fund such a project now.

> We can be confident that our galaxy has not yet had one

How can we be confident of that? For all we know the Cambrian explosion was precisely that.

Or - there's tons of lottery winners and we're bad at finding them.