Removing Butter Motion is a single button in the app. It takes the plugin out of Premiere, and leaves your account and everything in it untouched.
Before you start
Quit Adobe Premiere Pro if it's open.
Steps
Open the Butter Motion app and go to Settings.
Under Premiere plugin, find Remove the plugin ("Removes the panel and the background service. The app and your account stay.") and click Remove….
Confirm. A dialog asks Remove the Premiere plugin? ("The panel disappears from Premiere Pro. Your generations, presets and account stay. You can install it again anytime.") Click Remove to continue, or Cancel to back out.
The app removes the plugin, then shows The plugin is removed.
What stays and what goes
Removed: the plugin inside Premiere, including the part that does the rendering.
Kept: your account, plan, credits, saved presets and render history. They live on the server and in your account, not inside the app.
If you reinstall later, sign in again and everything you had is right where you left it.