Source: we am a hiring manager.
Personally, my experience has been that pre-covid, majority of interviewers were assessing your problem solving ability and if you can code the algorithm that you came up with. Getting the most optimal solution and fixing all edge cases for all problems in all interviews was not strictly necessary. But these days, even if you have the best solution coded up for 3 problems and missed one edge case in the 4th problem, you are not “good enough”. At one place, I was dinged for not thinking of the edge case before I wrote the program, even though I caught it while coding it up, in spite of having the write solution for the other 3 problems asked in the 2 coding rounds. It is a tough market, and probably tougher for you. Good luck mate.
That said, I interview in silicon valley and I'm a mixed race American. (extremely rare here) I think a lot of people just don't want me to pass the interview and will put up the highest bar they can. Mind you, I often still give optimal solutions to everything within good time constraints. But I've practiced 1000+ problems and done several hundred interviews.