@hydrocynus hello and welcome to the
Commercial Drone Pilots forum. We are glad to have you on board. I'm confident you'll find lots of helpful and enlightening information throughout this forum.
If you haven't already done so, consider adding your
LOCATION to your forum profile to help us know where you are when you post suggestions or ask for assistance. It helps a lot more than you might think especially because this is an international forum with members from all parts of the world. Here's a direct link to yours:
https://commercialdronepilots.com/account/personal-details
Keep in mind that a Part 107 is a lot more than a "Commercial" license. Unfortunately the FAA screwed the pooch when they allowed the name "Commercial Drone License" to be used because it's legally called Civil Operations. We are ALL Civil Operators unless we are flying under the Hobby/336 protection. If you're not flying for hobby you're a Civil Operator and thus required to be carrying Part 107 credentials.
Gold Seal UAV Ground School is an excellent option for professional and indepth training. They teach you the subject matter so you can gain the knowledge and use it going forward as opposed to "learning to pass a test'. Best of all they guarantee you pace.
They are also a SPONSOR on this forum which means a lot because without our sponsors this forum wouldn't exist.