To clarify, I'm not talking about simply reiterating the opinions of others when I'm not qualified, I'm talking about following the coversation that's happening around a game so I know what areas to address, and then going back and playing the game with that in mind in order to properly evaluate it. This is HOW you research something that you aren't necessarily an expert in.
This isn't because you CAN'T review a game in a vacuum on it's own merits, but it might not be useful to the audience that's reading. Like, I haven't played FIFA in like at least 5 years, and if you asked me to review it, I could certainly tell you what my experience was, but I'd struggle to compare it to other recent entries in the series or competing games, and that's going to make my review shitty for most of the people who want to read a FIFA review. So I'd read up on what has been changed and try to evaluate that as I play the game. Actually becoming a first hand expert and playing a half dozen other similar games at the same time is not realistically an option given the week-to-a-few-days that you generally have to write a review.
But it's still a kind of influence. My review is being impacted by what others have said in a meaningful way. But it's in no way plagiarism.