SemiAnalysis did a test on Anthropic/Claude subscription plans, running long horizon tasks until they maxed out.
The subscriptions are far more generous than API pricing.
When I first started using these tools I went the API route as my personal usage fluctuated a lot. But after a couple of months it was clear this worked out a lot more expensive and so switched to the paid plans even if not using all the quota.
Go with the paid plan.