Start by understanding the role level and total compensation structure before giving a narrow number.

You can say that you are primarily focused on fit and level, and that you expect compensation to be consistent with the firm's range for the position and market.

If the recruiter requires a number, give a reasonable range rather than a single point and clarify whether you mean base salary or total compensation.

For experienced hires, also consider bonus, signing support, retirement benefits, and any compensation you would forfeit by leaving your current employer. Keep the tone practical, not adversarial.

I think the key is making the logic easy to follow. Even a rough estimate sounds stronger when the assumptions are explicit.