Yeah, this is the exact pain I see all the time in mobile acquisition. People obsess over "warming up" their ad accounts or email pools, but the real killer is targeting and creative quality.
In my world, it's the same story: if your CPI is high because you're blasting install ads to the wrong audience, no amount of "account warming" or budget smoothing will fix the crash in retention. You'll get a flood of low-quality users who drop off at onboarding, tank your LTV, and destroy your domain or App Store signals.
Warmup tools are a crutch. They'll help with deliverability or account health for a bit, but they can't polish a turd list. I'd rather spend 90% of my time honing targeting, testing screenshots, and tightening the onboarding flow. The warmup stuff is just a tiny hygiene step, not the strategy.