The migration from proprietary GPU drivers of Nvidia towards open-source for the R555-R560 series involves significant security, performance, and feature implications. In this paper, we present a new methodology to improve the security posture of open-source GPU drivers while ensuring optimal performance as well as full-feature support. We are particularly concerned with side-channel vulnerabilities that can be exposed during GPU operation. Our approach is based on (I) identification and mitigation of targeted vulnerabilities using multi-layered security architectures, (II) integration of advanced cryptographic modules with minimal overheads, and (III) runtime monitoring of potential side channels through hardware-like preprocessors. The results show that our proposed implementation tolerates minimum performance degradation under several benchmarks and real-world applications against a variety of attack vectors. Likewise, we also perform a comparative analysis between proprietary driver implementations versus their corresponding open-source drivers concerning features and computational performance to gauge possible challenges influencing the process without compromising functionality or impaired performance for R555-R560 series Nvidia GPUs.The insights in our research shall be beneficial to end-users interested in adopting GPUs extended with secure software stacks using FOSS components as well as developers who intend to transform future iterations of current loyalist vendor-locked GPUs equipped with high-performance hardware features stable/secure firmware into humanitarian promise designs fostering privacy by design principles.