I think that's an unreasonable request for clubs like Rouvy, Nike and other big companies that have Strava clubs. This only started recently, so it's confusing to me how it's not possible to fix. 

Is their any setting to stop , fed up with notification

I’m also getting the notifications when someone posts in a team or club and it’s very annoying. Something changed recently, please escalate to Strava team to reverse back the change. 

Thought this had stopped, but I started receiving them again recently. I had to leave the club.

I’m getting New Post notifications from random Strava users related to challenges over three years old. I’ve searched settings but can’t find how to stop these very annoying posts. 
Strava administration - please provide a fix

I just left the Chicago Area Runners Club (CARA) on Strava because Strava has chosen to push their posts into my Notifications before developing the Notification On/Off switch.  

Let me know when I can sign up for Strava groups again, Strava. 

I've started seeing posts from the group "Parkrun UK" in my notifications. I can't seem to turn it off.

Somehow, after getting better, this just got significantly worse. Look at the response to this post I was notified of. I’m not even in that club. These “remove me” comments go on for about 75 people. I doubt this is what Strava was striving for.  

Here's. How you remove the group notifications it took me a while to figure out and it's a bit of a processes. You go to each group so say zwift group, go to the Zwift feed page then goto the profile by clicking the icon

, there will be a gear in the top right of the screen then there will be an option to see when a post notifies you. See two pictures above! Hope this is helpful 

 click group icon to go to their profile page forgot to circle it.

 five steps to disable 

 this will disable, you'll need to do for every group

I changed my setting to that months ago and it's made no difference 

I have left clubs, because some of them are lonely and post many times. I don't want to go to each individual club and disable the notification. The fact that there is no global notification settings (global means for all clubs and all apps and website with one single checkbox), it only means dark patterns. Marketing team says yeah go implement it tonight without a grain of UX research. It adds up to user frustration. But you win for now, since your major competitor doesn't provide ride data as you do.