Stay or Leave my Nonprofit After Several Years

I've been working at my current nonprofit job for over eight years in fundraising. It was my second job out of college and I grew with the organization. I love the mission, the community I serve, people I work with, the projects I get to work on, and get decent benefits except the pay is below average and promotions rare. After working in corporate, it was my dream job. Over time, as I gained more responsibilities and projects, I've started to become more burnt out, so tired, and feeling incompetent on some of the work I've been given. Recently, I've been tasked to put together a major gifts campaign and endowment but with little guidance or training on what to do. It's more go figure out what to do on your own and we'll "support" you along the way. There's a lot of pressure to be successful and exceed our revenue goals even though I don't know what I'm doing half the time.

I talked to my boss a few times about my burnout and work and they exude a toxic positivity that things will get better once we hire a new person. They even seem overwhelmed and overworked too. I've talked to other people who are in the same boat. People are not getting paid enough. They're also tired and overworked, but the mission is good and people aren't bad and you get health insurance, so why leave?

I'm at a crossroads of what I should do. I get to work remotely and have a lot of autonomy to dictate the direction of my work and make decisions. I do work on a small team, but we all do different aspects of fundraising and don't work together often. We're supposed to be hiring a new person to help me out with the admin, data tracking, and grant reporting which would be helpful, but I feel like this is their way of freeing up my plate only to pile more onto it. I'm already working on stuff outside my job description. I barely will have time to recruit, onboard, and train a new staff member with all the other work I'm tasked to do. I'm worried about leaving behind all my work if I do decide to leave. Maybe I'm too comfortable in this job, which is why I'm so conflicted. I also don't want to duck out after we just hired a new development person and wonder if I should just suck it up for a little longer.