Some insights from my research on planning my career. Note that job roles are subjective to the companies:
See the potential career growth induced by gaining skills (not experience). Platform engineering is a supporting job that focuses on devops and cloud orchestration that can go as far as cloud architect. Core engineering can you take you as far as software architect.
Now see the potential career growth based on experience, cloud architect and software architect are both technical architects and both can become VP of engineering in their own departments. But the real difference comes at the need of the department itself. VP of engineering (core) is the major department that directly deals with the product development. This can take you to the CTO/CEO level if you are into management and wanna explore. Your skills to build a product would be highly appreciated in a startup. As for VP of engineering (platform), your job is still about cloud orchestration and helping the team manage servers. This is also crucial but this might not be very aligned to the core product so involvement is limited to running operations. I think the executive level should be COO. But this is just insights of what I learned from different sources. Maybe platform engineers can also become CTO if the company's main product is related to devops.
Coming to my personal career, I was confused between backend development and security research. I realised that backend development goes as far as CTO/CEO while security research is more of a hobby rather than a real job. Yes there are jobs, but very limited and their work is very sophisticated and less paid for the skills they bring. So I kept doing security research aside and went out for interviews for backend dev. But I think my security background is not going to leave me for life and I do way better in security than backend dev. So even when the pay is higher in core engineering, I am continuing with security research. Maybe this will help you