Partially supported by Fundação para a Ciência e a Tecnologia (FCT), Portugal, within the scope of the projects SpectralOPs - Spectral Optimal Partitions: geometric and numerical analysis, reference 2023.13921.PEX, and via the research centers GFM - project UID/00208/2025, CIDMA - project UID/04106/2025 and CAMGSD - project UID/04459/2025 - IST-ID under the FCT Multi-Annual Financing Program for R&D Units.
