Open Science is increasingly central to European research, enabling cross-sectoral access to and reuse of scientific data. To support secure, FAIR-aligned data sharing, the European Commission has launched flagship initiatives such as the European Open Science Cloud (EOSC) and the Data Spaces framework. This paper aims to discuss EOSC and Data Spaces, two of the main European initiatives designed to achieve this goal. This study will be carried out by analyzing the different strategies to achieve such a secure and cross-domain environment, as well as how these strategies can be used to contribute to the development of open science in Europe. Within this scope, the EU-funded TITAN-EOSC project will be discussed, describing its technical architecture, main objectives, and relating the key points to EOSC and Data Spaces. The main synergies between the project presented and the initiatives discussed will also be considered, highlighting how they concur with each other.