I actually think it to some extent depends on the function of the perfectionism and where it comes from.
For me, perfectionism is definitely an overcompensation for feeling like there's something kind of abstractly defective about me. Couldn't tell you what it is that is "wrong" but I feel I'm "missing something" - there's nothing particularly criticism-worthy about me (in my opinion) but I tend to suspect that I lack the essence that makes people loveable. The reason I "know" this is because when I was growing up everyone acted like this was true, but no one ever explained what was missing with me. I picked up friends very easily but I never felt I belonged. I was described as "weird" by the other kids and spent most of my time excluded but very rarely actually disliked. It's like everyone agreed there was something odd and uncomfortable about me, but no one could put their finger on what it was. And I just kind of internalised that as an image of myself. In reality, it wasn't that there was something wrong with me, it's that my parents were maybe a little.....different....and so the world outside my home was harder to fit into.
But while all that was going on, I was top of my class, played several instruments and was good at creative writing - so I also got a ton of positive attention for being "special". I was "gifted" - the "star". I got used to seeing it like this: It's ok that I'm "different" and I can't be part of society because even if no one will ever truly accept me, everybody admires me. So being impressive and high-achieving became my way to have positive social interactions in place of actual genuine connections with other people. But of course, you can't ever fill up on high achievement when what you need is a companion, so you'll always feel empty. You think that if you just do something well enough you'll feel whole and complete, but nothing is ever "good enough" because it never fixes you. Also, IME, you can get really obsessed with your work but then when the project's over and you only have the rewards, you don't feel proud, you just suddenly realise how lonely you are. That's happened every time I've reached a goal. I've spent years completely obsessed with getting to where I'm currently standing, then I sit and look at my "reward" - that award or new job or whatever - and think "I wish I had someone to share this with".
For me, understanding this history and telling my own story to myself made it much easier to speak back against the perfectionism. Whenever the self criticism begins I remind myself that it's all based on a lie I grew up with - that I need to be "the best" in order to be seen; that I am invisible unless I excel. And then I just kind of make a choice. Do I want to keep telling myself that lie? And do I want to make the rest of my life the same torture it has always been, or do I want to start again? In every moment I have the choice to treat myself differently to how I was treated growing up. I have the choice to decide that I am loveable without achieving, and part of loving myself is giving myself space to enjoy my work and to make mistakes and to not have to overcompensate at all.
It takes a lot of practice, but over time you learn new habits of taking this warm, loving approach to yourself, and then the need for perfection slips away.
Anyway, really long post and probably not applicable to others, but for me knowing my story really helped me understand why this idea that I'm not good enough as I am is not true. It helps me to look at that abstract feeling of "something missing in me" and tell myself: "Of course you feel that way, that's the way you were brought up, but that doesn't make it real".