For a developer who is flexible, adaptible and passionate about both - web developer and Machine learning, what should be the atmost quality suggestion to make their spare time useful for learning either:

1. new Web technologies/frameworks or any SDLC technologies
2. Or learning machine learning, Deep learning, AI and then try to focus on solutioning the knowledge gained with some practical manifestation of many more prevailing challenges which ML could solve easily.

PS: No diplomatic suggestion.