In the "notarization" step there might happen some basic scanning.
An signature is not sufficient ou suppress that warning, the pkg
has to be uploaded to apple to get "notarized" in addition.
As far as I'm aware there should be an option to install anyway, see https://support.apple.com/guide/mac-help/open-a-mac-app-from-an-unidentified-developer-mh40616/mac
That link should be added to Download-page as long as the
installer does not have a valid notarization.
I thank you all for your input BUT,
The issue is I am STILL NOT able to use your software, despite having a need for it.
Really???
Is an Action as Press key Ctrl, Rightclick installer in finder,
choose open from menu, release key Ctrl really preventing you from
using FirebirdSQL?