No, this won't work. Sellers have groups (on FB or dedicated sites) where they organize people to buy their product for free or almost free (they provide a discount code) in exchange for a review. They don't usually tell you directly to give them a 4/5 star review (although I've seen that too), but tell you to contact them first if you are not happy and if you leave a 3 star or less review they simply don't give you any more free stuff... or worse!
When I say worse, this is an example recent experience of mine. I have a thing about exposing scams like that, so I joined a group to get a "Best Seller" pair of binoculars that was receiving suspiciously raving reviews, without paying full price. I reviewed it and, sure enough, it was really poor quality for the price (even magnification and effective aperture where nowhere near the specs), so I wrote a (rather generous in hindsight - probably because I had reviewed really horrible binoculars recently) very detailed and technical 3-star review that basically said these are worth less than half the price. I did get a message from the seller "thanking me for not posting the review", which is an interesting way of requesting I remove it, but that's it. Anyway, this review started to slowly get up-voted (about 1 vote per day) so it was on the front page after a few days. But one day, I see a dozen sudden downvotes, and the seller claiming I am a competitor in the comments (they actually claimed I own Agena Astro!) - they even messaged me to tell me I was reported for malicious slander to Amazon etc. So the review got buried. If you are wondering about the down-votes, I got emails from people whom the seller had asked to down-vote me (members of their review group), so that's how that works.
I don't think it is hard for Amazon to fix these issues. First of all, they should remove (or not "count") reviews that have used a promo code. That's the primary method these review groups work. Then completely ignore reviewers who drop-ship (another method) or work exclusively on promo codes - there are Top-100 or even Top-50 reviewers that are "serial reviewers", get everything for free with a promo code and always give 5* reviews (e.g. Top-50 on Amazon.co.uk). Lastly, run an analysis to identify downvoting/upvoting "rings", i.e. users that are asked to mass downvote legitimate reviews.
Up until a few years ago, I thought Amazon reviews were great at helping me figure out what to buy. Now, I only read reviews from items that are sold by Amazon directly, so that no seller has messed with them, the rest are not helpful at all.