Eye strain is much worse, long term, with dark mode. (If you know anything about depth of field in optics, and what your pupil does, it is no shock.) Fix your room lighting if light mode bothers your eyes. Long topic:
Some young developers have worked out some hacks recently, so they can destroy their eyes faster. I'm not going to help you find it.
Dark mode is the hipster thing, but you will regret it.