The best training is practice, practice, practice! But sometimes online training can spark new ideas and techniques. If you have any to recommend, please post here and what you liked about, i.e.. what someone could expect.
This inspiration for this post came from this article that ranked online courses. I am not familiar with this site, so take with a grain of salt!
https://expertphotography.com/best-online-photography-courses/Cheers,
Rob.
