It is almost impossible to answer this question, because it really depends on what you need to achieve. I suggest to take a look at this thread, which lists all top solutions: https://forum.unity.com/threads/wha...of-available-network-solutions-assets.609088/
I’ve been using photon but it’s hard to have cheat prevention and I want to try mirror but it has only one connection or so that’s what the doc says
You're not getting any recommendations for several reasons. The "best" networking solution depends entirely on what you're trying to create. It depends on your desired network architecture, cost structure, anticipated network traffic, target platform, etc, etc. You haven't mentioned any of that. As far as "easiest", there are no easy real time networking solutions. You're going to spend around 2/3 of the total time writing your game's code just on networking. So it is like asking which is easiest, fighting with your bare hands a grizzly bear or a mountain lion? There's probably a real answer to that, but the question itself implies a misunderstanding of what really is involved. Plus, the only people who could answer what is best and easiest would be those who have tried all the available options. I'd be willing to bet the number of people in the world who have done so is close to 0.