For Amazon FBA product research use AMZScout tools. They have all of the needed features: a detailed analysis of products and niches, keyword research, fba calculator, and more. And more importantly, there is a free trial.
Yes, you should avoid this product. As for a strategy, it can be great for a product to have a lot of variations, but it’s okay to compete against them if you have another offer in design, quality, details, etc. Also, if you want to do reselling, yes, 20+ sellers is a lot of competition for a product. Go to the Amzscout Pro Extension, find the column “NUMBER of sellers,” and sort by it. The products that have from 2 to 15 sellers are the lowest competition and the best option for you. If the seller count is just 1, it could be a private label product, so you wouldn't be able to sell it.