For a good general source if you want to learn a lot more from a good popular science point of view (but one that takes great care to not accidentally mislead by oversimplification as often happens with popular science) about general relativity and quantum mechanics, try PBS Space Time, especially after Dr. Matt O'Dowd took over as host and main writer.
https://gizmodo.com/why-cant-einstein-and-quantum-mechanics-...
https://www.theguardian.com/news/2015/nov/04/relativity-quan...
https://en.wikipedia.org/wiki/Problem_of_time
https://physics.stackexchange.com/questions/387/a-list-of-in...
For a good general source if you want to learn a lot more from a good popular science point of view (but one that takes great care to not accidentally mislead by oversimplification as often happens with popular science) about general relativity and quantum mechanics, try PBS Space Time, especially after Dr. Matt O'Dowd took over as host and main writer.
https://www.youtube.com/c/pbsspacetime