Hey there! Your product limit is increased when you upgrade your subscription. On the forever-free starter plan you've got an import limit of 500 products. If you'd like to launch with over 500 products and process more than 50 orders per month, you'll need to upgrade to the Oberlo basic plan which costs $29.90/month.
That being said, may I suggest that you launch your store with less than 500 products?
Generally, it's costly to advertise that many products at a time, and until you get your marketing mix optimized, in my opinion less is more. That way you can control your advertising spend in the early days. As soon as you are approaching that 50 order mark, and making some money, then that would be the best time to upgrade. In my experience, stores with fewer products and a more focussed approach in terms of who you plan to target is more effective than having thousands of products in a variety of niches.
Here's a breakdown of Oberlo import limits and order limits on each tier. And here is a great article on niche vs general stores. As always, the community is here to help, so thanks for asking the question and reaching out!