If it will start up in "Safe Mode" just fine, then there is something (software related) on you device that is causing the problem. The system restore and reset, unless they were wiping all things on the device, then they would not have removed any software, virus, malware, etc., problem.
From "Safe Mode" have you checked for malware, viruses, newly installed software and updates? That is where I would start. If that doesn't resolve it then I would look at doing a full restore of the system. Which will require you back up all your personal stuff somewhere else. Another device, cloud account etc. Otherwise it would all be lost. Then try reinstalling the system from scratch.
But that is a last resort. Start with checking things and scanning the computer from "Safe Mode". And make sure your program can scan for both viruses and malware as they aren't the same.