I cannot find the option in Salesforce to uninstall the 8x8 Integration for Salesforce.
- Log into Salesforce as an admin.
- Enter Lightning Mode.
- Go to Setup at the top right.
- Search for and click on Installed Packages.
- Uninstall the package.
The folder/object structure in Classic vs Lightning mode is not identical, but the Installed Packages area and Uninstall option are both generally available to admins, and are found by navigating to Setup in either platform, and then by searching for Installed Packages.