If it weren't implemented by cloudflare natively, would you be ok using a library or something that wraps or hooks onto your IaC to wrap entry points with a worker (proxy or circuit-breaker, conceptually) with various types of limits (real-time estimated spend, or just counts of operations, or just a on/off switch wired to an email alert). I'm pulling a few of these threads at the moment since I've been ramping up my cloudflare usage.