Most 'source of truth' problems in product development aren't really about the source of truth at all. They assume that everyone wants the truth, that they can agree on what truth they're seeking, and that they're willing to put in the work to forge coherence when there are different versions of the truth.
Your team has a list of initiatives. Some of those initiatives involve frequent releases. Some of those releases are visible to customers, while others are invisible or behind a feature flag. Some initiatives result in a marketing-supported launch, and those launches are assigned different tiers. Sometimes the relationship is 1:1 (initiative to launch), but sometimes the launch itself is a multi-phased initiative linked to the "phases" of the original initiative. In many cases, initiatives are selectively grouped into a launch. Not all initiatives result in a launch.
Wait, there's more. The company chooses to understand allocation through multiple frames, including capex/opex, strategic pillars, market segments, new capabilities vs. optimizing existing capabilities, and strategic horizons. And throw in goals—some are delivery-based, some are outcome-based. Some are linked to Initiatives (the initiative came first, with the goal being added later). Some preceded the initiative (the goal inspired the initiative).