If your struggling to find a decent fire team, especially if you have joined late, I have set one up called "Destiny Late Starters" to hopefully create an active Clan that doesn't require a join confirmation to help with getting fire teams together with these clan related achievements in mind too.
I have found many bigger groups/clans to be not as active.
https://www.bungie.net/en/Clan/Detail/1652851Make sure you set it as your Xbox account clan as well. You should see the option where you clicked request to join