You can export as many profiles as you want in the CRM. However, LinkedIn limits search results displays to 1,000. As a result of this, you can't unfortunately export more than 1,000 leads per search (up to 2,500 if you have Sales Navigator). If your search includes more than 1,000 results, try and split it into several smaller searches so you can eventually export all the leads from the search results. Here is an article
that explains how to export more than 1,000 prospects.