Not exactly learning, more like training, but for me the biggest ROI was Leetcode. Probably not something you want to expense through your company though, I paid with my own funds.

Outside of this, I am paying for DeepLearning.ai specializations on Coursera and enjoying it a lot. The material itself can be reconstructed from free web resources and textbooks but the value is in systematic syllabus, quizzes and programming assignments.