Sometimes, people will suggest that using 3rd party tools will cause your posts to not get as much reach.
As a creator, I’ve had that thought in the past as well. When a post doesn't do well, it's very easy to reach for possible explanations, and the 'tools explanation' is a common one.
But every time I think that, someone with tons of engagement reminds me that I’m imagining it: they use scheduling tools, they remind me, and there's no discernible effect.
Then I remember: if I'm unhappy with my content performance, I just need to work on my content :) My hooks, the strategy, everything.
So, no: the use of 3rd party tools does not appear to have any effect on post performance as far as we've been able to tell, although these rumors have been circulating as long as there have been scheduling tools.
So, what DOES improve post performance?
Having an engaged network of followers
Writing amazing content targeted well to your audience
Creating a bangin' hook that gets peoples' attention
Writing comments on other peoples' content before your post goes up
Responding to comments on your post once it's published, for at least the first 10 mins