This sounds like a good question to ask chat gpt :)
Basically, I'd do the following:
1. Figure out what stands at the overlap between what you're good at and what you're interested in
2. Then double down on that. Get additional education and practical expertise. Invest yourself as much as possible at this stage to become 1-5% within your file.
3. Identify firms / commercial outlets that can / are interested in monetising your skill (e.g., consulting firms looking for experts within a certain field to improve their own value proposition).
I would be happy to share my thoughts on it:
If you would like a more detailed discussion on how to address your specific situation, please don't hesitate to contact me directly.
You need to spend time in a specific field/area. You need to work and learn in this area and get to the point where you are then…an expert.
This is not something that is counted in months but rather in years.
it is a combination of practical experience (project work) and functional/industry specific training that makes you an expert in a consultancy. At some point you are able to chose between general and expert career tracks. Details depend on the specific firm you join.
Becoming an SME is not a means to an end. Instead, people take a certain career path based on their passion for the subject, often including PhDs, spend time in academia and/or industry where they're working on one broader subject only for years, and typically see themselves in that field permanently. They don't do that thinking that they'll end up at MBB one day.
In my case, I hold various degrees in Geology & Geophysics and spent 6+ years working in upstream oil and gas projects around the globe. That could have been just enough to set me up for an SME path in MBB, had I not wanted to pursue the generalist path at McKinsey.
My point being, becoming an SME is something that takes years and isn't a viable strategy if you're thinking about it as a potential USP for entering MBB for example (I have to guess a little here where your question is coming from).
Hope this helps a bit. Best of luck!