It’s become nearly impossible to gauge a product that has mixed reviews without carefully reading a good selection of both good and bad reviews. What I’ve found is that a lot of reviews, usually bad ones, can be discarded within a few seconds because they have nothing to do with the product - it’s about Amazon’s delivery, or the freight company, or something unrelated.
The next category that can be discarded are the ones who clearly bought the wrong product or had unrealistic expectations (of that product, product type, price point, etc.)
The ones that really make me blow a gasket are the positive ones based on a few days or less of ownership - sometimes MUCH less. “They just installed my new fridge and it’s AWESOME - five stars!” or even - and yes, I’ve seen this on more than one appliance review - “this [appliance] is by far the best and great and a value and awesome and incredible and so forth and I can’t wait until mine gets here next week.”
There’s no short cut, but if you read through representative reviews for ones by people that sound like they know what they are talking about, actually address the item’s function, quality and value, and seem to be based on some significant amount of time or experience with the thing, you’ll find a prevalence near one end of the review scale or the other.