There are foods you can eat that will help thicken up the output and give you better control over leaks. Potatoes seem to help just about everyone to some degree (baked, mashed, french fries, crisps), rice, pasta, bread, CHEESECAKE, applesauce, gummy bears, marshmallows. Psyllium husks are really good for this.
As for gear, I don't know what all you have tried, but I've seen many people on this forum in the UK speak praises of Salts and Eakin rings around the stoma to help prevent leaks. Brava strip paste and Coloplast bags work great for me, but not for everyone. If you are having trouble with the very edges of the bag coming loose and this leads to the leaks you are having, there are Brava extensions that go around the edge of the baseplate and give extra hold to the skin. You might also try a belt to help hold the bag in place. Another thing that you try is using tincture of benzoin. Its a very safe skin glue. It is used after surgery to hold bandages on. This works great with stoma bags and is easy to remove from the skin during bag changes.
I wish you the best. Don't stop trying out stuff until you find the right combination. There are so many options and new things coming out all the time. What works for one person won't always work for another.