Well, I've actually personally found issues with Unity's 2D URP shadow-casting system where it would unnecessarily be handling shadows outside of the lighting range depending on the scale of the object - I had to add custom code to the 2d shadow caster in order to make my previous 2D URP game w/shadows performant for that very reason, so it might be in general performant, but in particular the 2D shadow casting is definitely not perfectly optimized.
Also, I know for a fact that my raycasting is not the issue, as doing some quick profiling shows that the raycasts I'm doing are using a total of 0.4% of the CPU the game is using, which is an insignificant amount in the scheme of things. Believe me, I did try to bring that number down, but it was about sacrificing performance for the accuracy of visibility detection with my objects, and I wanted to be as accurate as possible so objects wouldn't pop in and out of existence while you could still see them.
I was merely suggesting hardware could explain the game being laggy for you but not other people (like myself), not that it would cause the game not to run. As I mentioned, I know for a fact that the text not showing up (which was the "browser issue" I was referring to) is due to an issue with TextMeshPro materials, not due to any lack of optimization.
Regardless I appreciate the advice. Sorry if I'm being defensive - I'm trying not to be but I know that I am to some extent. I definitely am not an expert on optimization (it is definitely one of my weak points), so I'll still definitely consider your advice for the future.