I alone will not be able to invest such an amount of money that will cover all the needs of the project, but I will probably invest a couple of ETHs.
Yes. 500 thousand dollars is not everyone has. And to invest such amount in one project would be very risky.
I know many people from the crypto industry who have sums much larger than 500 thousand. They came to the crypto market a few years ago and managed to make very good money on the growth of Bitcoin and Ethereum. But they also do not invest such large sums in one project.
In order not to invest all your money in one project a lot of mind and experience is not necessary. It is enough to think a little bit about what will happen to your money if the project does not fulfill its plans.