Same to you, @TripleE, thanks for posting. Club leaderboards are designed to track members on a weekly basis, with a leaderboard for 'This Week' and 'Last Week,' resetting weekly on Sunday at 12 am. Outside of that, clubs do not store historical data.
Club events can only be set up for one day, and although you could create multiple events to cover the 30-day period, they also do not include their own leaderboards. Activities from club events would be reported through the club leaderboard.
In the mobile app, clubs do report aggregate totals from all members per week. You could set your club's sport type to running and track the total distance covered by your club through the mobile app week over week to see if your members complete the goal after a month. Alternatively, you could create a post in your club so that everyone comments to add their running totals after a given period (up to you if you want to track that weekly or just at the end of the month). Reviewing individual profiles could be another way to review this data after a month.
Lastly, have you considered using Group Challenges? With a subscription, you can create unlimited challenges (non-subscribers can join or create up to three group challenges), and each hosts up to 25 athletes, including yourself as the creator. You could set up month-long group challenges so that everyone in your club is one, and then you can add those totals together to see if the club completed the challenge goal.
I know that our team is looking into improving Clubs on Strava again, and we'd love more feedback. During your challenge, if you come across any new suggestions, please create new posts here to share your ideas with the community!