I am looking for an alternative to Sqreen (https://www.sqreen.com) which was bought by Datadog and then sunset.

Sqreen was an application security platform. Pretty much what an Application Performance Management tool (like New Relic) is doing, but for security. (was featured a few years back on HN: https://news.ycombinator.com/item?id=20215483). The engine houses the Runtime Application Self-Protection (RASP), Content Security Policy (CSP) and Security Headers, and In-App Web Application Firewall (In-App WAF) layers that observe activity and block attacks from within your app.

I am now looking for a product with similar features now that Sqreen no longer allows signups.