Complex marketing automation logic?

Our SaaS is experiencing significant growth, and with it, our marketing automation requirements have escalated dramatically. We've moved far beyond the scope of basic drip campaigns and now require highly dynamic, real-time decision-making capabilities to personalize complex user journeys across various touchpoints. The standard offerings from most marketing automation software providers are proving insufficient for our current needs.

The technical hurdle we're consistently encountering involves implementing sophisticated, multi-platform conditional logic. Generic "if/then" workflow builders in typical Email Service Providers (ESPs) simply fall short when we need to factor in granular user actions pulled directly from our backend systems, integrate deeply with a diverse set of third-party tools (beyond simple webhook triggers), and then meticulously orchestrate branching paths across both email and SMS platforms simultaneously. We're looking for strategies or advanced marketing automation software features that enable more programmatic control over flow execution, driven by external data points and real-time behavioral triggers. How are others building robust, scalable flows that handle truly dynamic, deeply nested, and cross-platform conditional logic without requiring extensive custom middleware for every unique user segment and action? We're eager to learn about architectural approaches or specific platform functionalities (beyond conventional visual workflow builders) that successfully manage this level of complexity.

Waiting for an expert reply.