If your lower-tier clans aren't active enough with players - that only require barely 2 hours to run the event to get 20k - you can easily join a legitimate clan or grow your clan.
If you can't get your gold trophy by merely pulling yourself together then you placed yourself in that position deliberately.
Warlord to Warlord here, it's pretty damn hard to keep track and manage your clan's player base, especially when Warframe has its down times. I am Warlord of a Mountain Clan and yes, we did get the Gold Trophy. It took a few days and many painful hours. Some of our players have 20k scored individually.
Keep in mind. This is a Clan Event. Not a Solo Event.
For upper-tier clans, administration and getting many other human beings to do the event is really difficult. Also, both Clans get the same reward despite you having to take 2 hours and other clans a whole week of grind. You should be happy to only have to do minimal work and get an equal reward.
Maybe you need some help? My clan can help you. Perhaps you should join 🙂