> I'm building a personal brand as an industry-focused research engineer ...
Meaning you're planning to run your own business.
> What value can an MBA add to my career?
It might make it easier to assemble a successful business plan for your consultancy, but acquiring an MBA for that purpose alone might be overkill.
> Will it enrich my career with management and business skills?
That depends. Are you anticipating that you may offer business as well as technical advice?