Pre-orders are always great for testing demand, eliciting end-user feedback and even generating a little revenue! You just have to be sure that you can fulfill whatever product or service the customer is paying for, beta or otherwise. Relative to b2b vs. b2c, I can't really speak to that based on the info you've provided.

To you success, Frank

Why would customers not be your #1 priority when creating your beta? They are all that matters!

Once you have a handful of pre-orders you'll be able to find common patterns across them - similar industry sectors, geographic locations, company size etc. which will give you a tremendous amount of data to help figure out your product/market fit.

Pour your time and energy into providing the product for the group of people who are saying they want it and putting their money where their mouth is.

If it is a physical product you could consider kickstarter to do that. LOIs from businesses coyld help to ger some bank loans. Start projects with business could help to get some money and feedback.