Let me give a non-answer.
Cannot compare in terms of their merit. Engineering and Physics have evolved into two worlds that are so vastly different to each other. More distant than you think. The fundamental difference of character being—you are not expected to elucidate everything in engineering. Take AI for example.
As for complexity—physics can be excruciatingly tortuous if you’re at the forefront. Otherwise, practically speaking, experimental physics is closer to engineering but with more rigor and abstraction.
Both have made the world we live in, in varying proportions. Both are worthy of your attention.