Back to Q&A board 
Congratulations on the offer! I’d keep both conversations moving while getting clear on the deadlines.
First, ask the company that made the offer when they need your decision. If you need more time, request a specific extension and express your interest. They may have some flexibility.
Then contact the recruiter for your preferred role. You could say:
“I’m very interested in this opportunity and would like to continue the interview process. I’ve received another offer with a decision deadline of [date]. Is there any flexibility to accelerate the remaining interviews, or could you help me understand the likely timeline?”
You don’t need to share the other company’s name or compensation. Just be honest about the offer and deadline.
Since you’re only at the second interview, there’s still uncertainty. If the timelines cannot align, assess the offer you actually have: the work, manager, growth opportunities, compensation, and whether you’d be happy accepting it.
If you would genuinely enjoy that job, accepting may be reasonable. If you’re considering declining it, make sure you’re comfortable with the possibility that the preferred opportunity won’t result in an offer either.
I’d also avoid accepting purely as a placeholder while planning to withdraw. Accept with the intention of joining.
A useful question is: “If the second company disappeared tomorrow, would I still want this offer?” That often makes the decision much clearer.