Even if you’re the weakest link, a good manager and good team would make sure to assign you tasks that match your level such that it all works out in the end. I’m a software engineer and I’m watching over a junior and a senior. One of them gets bigger tasks, one of them get smaller tasks. It’s similar work, but in the end I want both to have cleared the same amount of tickets and feel good about it. When I plan the next tasks, I think of “what can I give to the junior, what can I hand out to the senior”.

If you guys are always behind schedule, then some manager isn’t managing properly. It either means you need more team members, or your manager should discuss with you ways to improve your performance. But you’ll rarely find a team where every employee is top notch. Some people just work slower than others. It’s the manager’s job to deal with that.

As for the venting, I think it’s important to be mindful of other people to be on the receiving end. If you need to do that much venting you might want to consider a therapist, who might be able to help you deal those thoughts and how to manage them.