1. In case you haven't known, you can set the Planet Designation of your industrial worlds to "Forge World", and that will "shift one job from Consumer Goods to Alloy production" for each district, eliminating all CG jobs. It's already been mentioned above, but the post didn't spell out exactly what you need to do. In the screenshot below, you can see one of my "Factory World"s, that I have built for CG production (see item 2 below). I've outlined the planet production, only showing CG output, not alloys, and below the sector name you can see the Planetary Designation set to "Factory World". Clicking on the icon in that designation pops up the "Colony Designations" list, and there you can pick a different designation. As you can see in the tooltip for "Forge World", this designation will, for each Industrial District, shift one job from CG to alloy production, i. e. all CG jobs that there are.
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2. As also suggested above, if you have "Wary" or better relations with another empire, then they may be interested to directly trade with you, and CGs, like Food are valued highly as a trade good. In my current empire, I am producing 600 CGs and 6 alloys per month from jobs, But I'm trading 72 CGs and 1075 food in exchange for 300 alloys and 400 energy with several friendly AIs.
3. Once my ECUs are up and running I'll probably switch back to militarized economy and producing alloys myself, but until the Civilian Economy policy is serving me very well. See screenshot below:
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