Being a native app distributed only through the App Store, 1Blocker can be uninstalled in the same way as any other App Store app.
Here's how to remove 1Blocker from your iPhone, iPad, or Mac.
iOS:
On your iPhone/iPad, locate 1Blocker.
Touch and hold the app's icon.
Tap Remove App.
Tap Delete App, then tap Delete to confirm.
Mac:
In Safari, turn off all our extensions in Safari > Settings... > Extensions.
Quit Safari and 1Blocker.
In the Finder, navigate to the Applications folder and locate 1Blocker.
Drag the app to the Trash on your Dock or select the app and choose File > Move to Trash.
Go to the Trash and empty it.
Also, feel free to check out this article from Apple with additional ways of removing macOS apps: Apple Support Page
On a side note, no matter why you decide to uninstall 1Blocker, your feedback is crucial to us, and we would appreciate any comments on how we can improve your experience with our app.