Optics aside, before a raise is actually the best time to leave because it means that a replacement can be budgeted for in the round (I have a friend raising wi

Optics aside, before a raise is actually the best time to leave because it means that a replacement can be budgeted for in the round (I have a friend raising with the expectation of a new CTO at the moment, although that departure was planned). VCs in later rounds often prefer key roles to be occupied by hires they think are better suited to scaling a company even if the cofounders are willing to retain responsibility; a cofounder who questions their own suitability can achieve the same end with less friction. Provided they're convinced it reflects you doubting yourself rather than your co-founder or the suitability of the solution for the market, which may involves more honesty about how little you want to work on the problem rather than less. A team pursuing an adtech/defense/crypto pivot despite an original founder's visceral dislike of that industry is much less of a negative indication about its potential than a team pursuing it despite a founder's unexplained doubts (especially if you've been the lead on the commercial side). If your dislike of the new model is not that visceral then staying on as a paper adviser avoids the external appearance of serious discord, and phasing out your involvement avoids an abrupt transition, but you can't be dishonest about no longer doing the day-to-day stuff with investors.