Young HRBP here. Stay at a toxic big-name company, take a risky leadership role, or wait for mentorship?

I’m in my early 20s and have been working as an HR Business Partner at one of the country’s leading media organizations for the last seven months.
On paper, it’s a great place to work. Big brand, good exposure, and a role that looks impressive on my resume. But the reality has been completely different.
The work culture has taken a massive toll on me. My teammates constantly gossip about one another, and unfortunately I’m no exception. I’ve overheard conversations about myself, been excluded from discussions, and there’s this constant feeling that I’m walking on eggshells. Instead of collaborating, everyone seems to be trying to protect themselves.
Every Sunday evening I start feeling anxious because Monday is around the corner. Every morning before work, I have to mentally prepare myself just to step into the office. I’ve become irritable, my sleep has taken a hit, and even on weekends I find myself thinking about work. I genuinely don’t remember the last time I was excited to go into the office.
The strange part is that I actually enjoy HR. I like partnering with business leaders, solving people problems, and being involved in organizational decisions. It’s not the work that I dislike—it’s the environment.
Now I’m at a crossroads.
A small creative agency has offered me a role as a senior HR leader. The title is amazing, and I’d get to build a lot from scratch—policies, processes, culture, the whole HR function. The company is fairly young, has a small headcount, and is mostly made up of Gen Z employees.
Here’s what’s making me hesitate: I honestly don’t know if I’m ready.
I’m still very early in my career. While I’ve handled HRBP responsibilities, I’ve never been solely responsible for creating policies or setting up an HR function. Part of me feels excited because this could accelerate my growth. Another part of me is terrified that I’ll be thrown into the deep end and make mistakes simply because I haven’t had enough guidance.
On the other hand, I recently spoke to a distant family friend who’s a very senior HR leader with decades of experience at a well-known company. I wasn’t asking him for a job—I was just seeking advice—but he told me he’d be open to bringing me onto his team if things worked out. More importantly, he said he’d mentor me properly and help me understand HRBP at a much deeper level instead of expecting me to figure everything out on my own.
I’m meeting him this Saturday to discuss it in detail.
So now I have three possible paths:
Stay where I am and hope things improve, even though my mental health is suffering.
Accept the senior leadership role at the creative agency and learn by doing, despite feeling underprepared.
Explore the opportunity with the experienced HR leader, which may mean slower growth in title but potentially much stronger learning and mentorship.
Has anyone here made a similar decision early in their career? Did you prioritize title, learning, culture, or mentorship? Looking back, what would you tell your younger self?
I’d really appreciate perspectives from people who’ve worked in HR or leadership roles because right now I feel like every option comes with a different kind of risk.