Solving LeetCode problems in practice mode or in contests is going to help you with some of the skills necessary for interviews, but there will also be skills that it doesn't cover.
All you need in order to do well in LeetCode contest is ability to write code for rather trivial problems relatively fast and bug-free. Your good performance will confirm that you are capable of that - but it won't tell much about your ability to write readable or structured code, to explain what your code does, to prove your solutions, to estimate their time complexity, to communicate with the interviewer in general, to adjust to changes in problem details etc. In theory, you can win LeetCode contest while being really bad at all of the stuff mentioned above. While it is true that some of the things are likely going to be there from LeetCode practice, some of the interview-related skills aren't needed for LeetCode, and aren't covered by LeetCode practice.
LeetCode is a good way to practice, but it is not as good as going through actual interviews. Get some real interview experience, get some mock interview experience and feedback on those mock interviews - and that's going to prepare you much better. Of course, things like mock interviews are harder to organize - at the very least they require involvement of another person, ideally with a specific set of skills and experience; so if you can't easily get that, LeetCode will be a good enough alternative.
In the end, if you think that the main point of an interview is to solve a problem - you are getting it wrong. It is not about the fact that you solved (or didn't solve) the problem - it is about all the stuff that you did along the way.