Help Trying to find proper credit management for AI app

Been trying to build a decent credit system for our AI application for the past 6 months and still didn't get any good end to end solution from managing user credits to payments.

Here's is the list of services I've tried :

- Stripe: good for reg. subscription but had to implement to whole credit system on my own.

- Lemonsqueezy: Looks goods but their credit system feels like it was designed for traditional saas apps not for ai apps where i have to for credits for tool calling, llm credits.

- Lago: I tried this open source metering based as well but still not upto the mark for ai llm credits + tool calling.

what i actually need:

- Credit-based billing both recharge and post-paid

- Plan upgrades/downgrades with handling proration period

- Credit expiration

- Overage protection

- Team/organisation credit pooling

I'm literally considering building this from scratch at this point, which feels insane in 2025. There HAS to be something out there that handles AI app billing properly.

would love to know what are you actually using that doesn't suck? Please tell me there's a solution that works and I'm just too stupid to find it.