Major and obvious reason it to carefully examine what raises your cortisol chronically. What sources of stress can you cut out that raise your cortisol? Treat yourself like a VIP, everything that is too stressfull for you has to go. Learn to cut it out now before your high cortisol drains your adrenals and you go into more advanced stages of AF, where your cortisol will be chronically low. Yes you could take some adoptgens but those are bandaids compared to cutting out your stress sources.
Learn to meditate, 20 minutes of good meditation will lower your cortisol. Any relaxing/soothing light activites like taking baths will too, if your mind is calm as well.
Good diet, cut out stress and as a last resort: maca / siberian ginseng / cordyceps / reishi / ashwagandha / indian ginseng / vitamines.
So clean DIET, meditation, cutting out stress is KEY. The rest is bandaids.