Do you also feel like all the feedbacks on a landing page are fake?

That is a good point!

If it can be easily made up, it raises the question that the majority are fake. As you mentioned, they don't link to any social profile, yet again, it could be as well fabricated. To me, if the app doesn't provide a free trial, they don't matter. If they do not offer any trial, and you got to commit straight up, to me, it usually means there are red flags on the product. I usually go on Youtube and try to look at "tutorials" if they ever exist and check if the product is worth it.