Here's some stats for you, I don't want to discourage you, but you will need a very large budget to begin testing Amazon FBA products.
140.000 sellers had sales over $100k in 2019
2.500.000+ active sellers using Amazon FBA last year
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5,6% of Amazon FBA sellers are making over $100k in turnaround. That's not even close to a full-time income.
In my opinion, it's a really tough market, and I'd recommend you dropshipping instead. That way you don't have to rely on someone else's platform (and don't have to order a ton of stock).