Just hide the details and put some jargons (AI/ML to detect behaviour etc :) and give an enterprise look and feel.
"Besides, we strongly recommend to let our JavaScript file blend in with the rest of your application's JavaScript. Webpack, compress and uglify the best you can, to make the code responsible for validation as difficult as possible to find and break."
That's not insanely high - that's pretty common for B2B SaaS apps.
The most I've been quoted for SaaS was more like $100K per user per year...
All in all, it's not unusual to pay 10k, 30k or even 100k USD a year for a core technology like that. For example, self-hosted JIRA costs 8.3k USD per year (if you want updates) for 100+ users, and you usually have several services just from Atlassian in this price range.
Also please consider making this a B2B enterprise product. To do that the main thing you need to do is hide the price or put insanely high prices. like $999 per year per license and above. If you are hiding prices, put a button to contact the sales team, which could be your phone number to start with.
Also put some white papers and add a lengthy demo with your own voice with an actual project, like Wordpress being protected and ask them to contact your sales if they need to enable the protection in their software as well. The demo could be put behind a sales form to collect contact details.
And hide your technology details. They don't need to know how you do it. Just give instructions on how to put enable your validation. Since you don't have a free tier it's very easy for you to validate your project's success. Just reach out to X potential customers (it's very easy for you to figure out potential customers too) and ask them to try your product. Give a 6 months money back. I
p.s. A great sales article I found on HN this week: https://stripe.com/atlas/guides/ama-steli-efti