Much has been said about synodality in relation to internal Catholic reforms, yet far less attention has been given to the need for a genuinely ecumenical form of synodality capable of strengthening everyday interdenominational practice and shared Christian witness in the public sphere. Speaking "with one voice" does not occur automatically at the level of institutional representation, but depends on coordinated and credible practices of cooperation among Christian communities. In confessionally homogeneous settings, synodality therefore tends to remain an ad intra reorganisation of ecclesial governance, leaving interchurch relations largely at the margins. Based on comparative observations from majority-Church contexts in East-Central Europe, the paper shows that 'ad intra' synodality often stabilises existing asymmetries rather than disrupts them. The majority Church continues to define the terms of ecumenical engagement, control access to resources, and set the agenda of cooperation. This exposes a theological-practical divide between institutional rationality (ratio), which privileges procedural order and organisational control, and the affective and relational dimensions of ecumenical life (affectus), such as experiences of recognition, trust, and belonging. The paper suggests that institutional anxieties over potential member outflow to smaller Christian communities foster a defensive mode of ecumenism oriented toward managing confessional risk rather than cultivating mutuality. Paradoxically, recognising confessional diversity as an internal dimension of ecclesial unity may reduce affective vulnerability and mitigate conversion motivated by relational wounds or protest rather than sustained doctrinal disagreement. The paper outlines how reconnecting synodal reform with grassroots ecumenical practice, and complementing it with more relational and polycentric models of unity, can offer a more credible response to structural inequalities between Churches.