First of all, in general it is possible to win hundreds thousand of dollar with few hundreds dollar deposit if someone is lucky enough but this is not the main important thing because the most important thing is about whether the claim is proven or not. Secondly, I do not trust trustpilot at all no matter the review is good or bad because anyone can post anything as they wish in this review site even without proofs and the rating given will affect the overall rating. Lets say you own a casino and you want to have a good rating in trustpilot, you can simply create many accounts and give the best review for your own casino and you can do bad reviews for other competitors. Last but not least, we should never take any good reviews or bad reviews seriously when there is no single proof no matter where we read the review including in this forum and no matter who are posting the review so we can judge the review objectively.
I heard on other forums there are some people there that are making bad reviews on a target business or site. They have a guide on another forum that guides other people that to make money, they should make multiple accounts on Trustpilot and give bad reviews to the target business or site.
After destroying the reputation of that site, they are going to contact the owner to offer a service to change their review ratings on TrustPilot.
So what we see on TrustPilot reviews is not pure reviews for all of their customers; most of them are the attackers who just want to earn money from the target site, and they offer around $50 for 10 positive reviews only or a package just to change the ratings to higher than 4 stars.
That is why we cannot trust any reviews that can't provide proof, as they may be attempting to profit from negative reviews.