tl;dr: Graduating from EE with Ph.D. offers, but thinking about shifting to physics.
Background: I'm an Electrical Engineering and Chemistry major (weird combination, I know). I am now in my final undergrad semester and have 2 Ph.D. offers for EE.
Explanation: EE and chem is because of the way majors are "given out" in India based on your grades/ entrance scores. I never really enjoyed chemistry much but as I said, it was given to me. I did enjoy the solid-state and devices part of EE but never VLSI, circuits, etc. Now that I'm about to graduate, I'm recalling a time back in school where physics was the one thing I enjoyed most.
Question: Do I leave the Ph.D. offers and learn physics by somehow becoming a project assistant? Or do I convince my potential EE Ph.D. advisor to let me take up Physics courses while working for his project (which will certainly be very tough in the first 2 years), and possibly risk being miserable through my Ph.D.? Also, is it wrong to assume that if I liked physics in school I'd like it now?
Explanation for this sudden shift: I find upon introspection during this quarantine that I'd like my life's work to be related to the fundamental nature of things, not to some gadgets that us humans use to make our lives better.
Edit: Courses done before: Mechanics, Oscillations & Waves, Electromagnetic Theo I, Quantum Chemistry I & II (Average grade), Photochemistry & Laser Spectroscopy, Solid State Electronic Devices