I will advice you to turn on notification of new threads on service board so that you can receive email of new threads like new campaign. You can check some presently existing campaigns that you have interest in on service board and also turn on the notification on the thread.
Campaign managers do open slot or bring another new campaign, then you can apply. This will be a better way to join a campaign on this forum than waiting.
Since when you are back, you have some merits already, you are a good poster, post good and earn more merits from reputable members which will increase your chances to participate in a campaign.