Nobody wants a $100k one of a kind homebrew with poorly programmed rules, questionable reliability and serviceability. Might as well put blinking lights in a cab with a cool art package and sell it as an art piece. If you are truly making one machine, you don’t even need to license as a homebrew. Teams of experienced pinball professionals routinely fail at producing a fully coded ship ready machine in the timeline you are suggesting. You’re not looking for an investor, you’re looking for a fool.