I was just put on a performance improvement plan myself a couple weeks ago (looking for other jobs since). It sucks, and I still struggle with this myself, but trying to remember that my ability to perform in this awful system is not a reflection of my character
While there is some merit to looking at how a team performs and how this can be improved, this is not always the case. My experience with this as a worker and (previously) a supervisory position showed me that the bar for performance will always be raised.
You could be performing just as well or better than people previously in your position, but managers and capitalists will almost always push for more from you. Most think they need constant improvement and growth to justify their position and that of their teams and there can be a very real threat of losing your job because of this.
Just remember that your worth as a human is not tied to your job performance and the system you live in will always be squeezing you for more. You are not a robot. You are not a computer. Humans have limits and pushing yourself past those limits comes at the expense of the quality of your life.
Capitalism necessitates the exploitation of resources, including those of your body in the form of your physical and mental health. Do what you can to maintain stability and financial security in your life, but I suggest looking for work elsewhere if possible.
I think you're doing great OP! Rule #1 in every boss' playbook is to make you feel like you're always behind and always underperforming to squeeze every ounce of extra labor they can from you, as if stealing your surplus value wasn't already enough.
Once, I was given a week to do a project that would've normally taken double the time. But I was so afraid of appearing incompetent, especially because all the higher-ups will act as if it's no big deal and that these are normal expectations for anyone in the industry. Pulled multiple allnighters and delivered the project within a week. For a second I was shocked when they said they were surprised with how quickly I finished the project when I thought I'd just barely made the deadline, but then it became clear: these expectations are all bullshit. You can probably guess what my reward was foe being such a good little worker: higher expectations (and no change in pay).
Anyway long story short, feeling dumb and behind is exactly how they want you to feel all the time. If that's what you're feeling, frankly that's exactly where you need to be. I've fallen for this guilt tripping too many times where I sacrifice my own sanity, health and self esteem trying to appease demands because they have you convinced you're terrrible at what you do. Think about it: if you felt like you were one of the best at what you do, you would demand better pay, better hours, more respect. This is exactly what they engineer against.
Of course, these feelings of incompetency are hars to reason with when they convince you you're worthless, so I have a trick for dealing with it; might help you too: thinking to yourself "ok, self, let's say you're right. You conned your way into this job and have no idea what you're doing. Fucking brilliant! You're the EXPERT and getting away with it! Even though you don't know what's going on, while others are busting they're asses for peanuts, you're in the same position as them just because of your excellent skill at getting away with it! Let's see what else you can get away with!" Make it into a personal game into seeing how far you can stretch it with slick bullshitting and doing the bare minimum but it seem like you did a lot. (This is what salespeople mean when they say they're "rejection oriented" -- you make the goal in your head not the closing the deal, or in this case whatever goal your boss told you, but instead how far you can go before getting a rejection). And guess what? This whole economy runs on so much hot air that your boss will literally appreciate you more for this mindset: you'll be acting like one of them now.
You're colleagues should slow tf down. What's wrong with them?
Don't feel stupid. Capitalism is not set up to get the best out of people, and the effects of this have no bearing on your worth.
Have you been in your job/role for long?
3 years now 🥲, but many of my colleagues have double digit years of experience. I only have those 3 in my area. In fact this was my first job out of college
While I think you should always be open to finding new ways to do your job, it is noteworthy that you managed to stay 3 years at the place while 'underperforming' as you say. You're very likely doing better than you think. And comparing yourself to people who have double digits years of experience is unfair. Have they ever mentioned something about it?
It is completely normal to feel "incompetent" from time to time, maybe even your coworkers feel like that at this very moment.
It is definitely tricky to approach your coworkers for help/tips, there are some selfish assholes out there unfortunely but there are also a lot of selfless people. Try approaching one of the most experienced first, or maybe someone new that might also be struggling.
Keeping these feelings to yourself will only make the problem worse, you will start being paranoic and start thinking that youre gonna get fired every time you get an email/call from your boss.
Studying one's performance should not be something that one gets by looking at the people around themselves, but by looking at one's past and one's present. Give yourself time, you can do it.