pipes
Why does the bend point backwards before turning to the right and going to the main. And that "second" turn going to the right looks like an impossibly "short" turn. You have created one of the most convoluted toilet drains I have ever seen, (the dimesion is actually 135 degrees not 180 and it is for special conditions only), and it does not have a vent. Under floor copper lines CANNOT be soft soldered, and if they are they CAN pull apart or leak in the future. From your description, you did NOT have a plumber, you had a handyman doing plumbing.