What is the best way to get credit for a new invention if you can’t get a patent?

The best way? In fact, the most pragmatic way and the most frequently advised and successful way?

Start the company and do it.

Patents won’t make it successful.

You want credit for it? Invent it. Frankly, you didn’t invent it if you just filed and have a patent for it (and I know people disagree with me on that). What you did was wrote it down, uncovered the methodology, and then sought to protect ownership of it… but it doesn’t exist in practice so it isn’t yet invented.

That accolade goes to whomever brings it to life. And if that’s another person or company, good for them.

Second to starting a company and doing it….

Open source it or write a ton about it online

By way of that, obviously there would be some record of your socializing it first. Maybe that would attribute you as an originator, in time.

Keep in mind however, history is written by the victors.