I get the same error.
Changelog states that osclass is compatible with php 8.
Not a good answer from "MB Themes".
Please try again and tell us what might be wrong when you get the following error:
Fatal error: Uncaught Error: Undefined constant "WEB_PATH" in oc-includes / osclass / default-constants.php: 37
Or is it that osclass is not compatible with php 8?
I was able to reproduce your issue and will be fixed in 4.4.0, there was another issue with built-in database connection class that might cause issues during installation.
Thanks for bringing up this problem