Each brand of backwater valve has a different method for top removal.
Some use a 2x4 stuck into the top. Some have flimsy tabs on top like you've shown which say to hand tighten only.
Since yours is located in the sewer and covers the entire house flow, it really should be Normally Open. Which there is only 1 good version of that.
The Mainline #4963 with a vault built around it so that is accessible without digging as all backwater valves require inspection and maintenance / cleaning periodically. There is an aftermarket device for this BWV that has an alarm so that you are alerted to backflow situations and can stop using water on your side and avoid flooding your own home.
It should be a normally Open device so that air flow back and forth is maintained throughout the entire plumbing / sewer system.