Big4 Transaction services Senior Manager to Strategy& Senior Associate

I am caught with a dilemma. I worked in a Big 4 Transaction Services (FDD) for over 10 years and progressed from Associate to Senior Manager. During this time, I worked in Asia (4 years) and Europe (6 years).

Last year, I attended an MBA program in the UK (Oxford/Cambridge) with the goal of transitioning to mid-market buy-side roles. During my MBA studies, I developed an interest in Strategy Consulting and the commercial aspects of deals (CDD/deal value creation).

Despite the challenging market conditions, I received an offer to join Strategy& in their Deals Strategy ring fence in Germany.

The new position represents a significant step down in rank but offers an acceptable salary increase - a slight bump over my pre-MBA salary, which was already above average for pre-MBA salaries of my business school. I am concerned that this move could derail my career. Can anyone provide guidance on the pros and cons of this move? My ultimate goal is still to transition to mid-market PE, preferably in the UK, or move into corporate M&A/finance director roles in Industry. My thinking is that my experience with financial and commercial acumen will be valued by future mid-market PE or industry employers. Am I mistaken?