Are Apollo leads being overused/milked by everyone, causing poor results despite sending 3,000 emails?
It depends on where you're selling to; right now it's August, and many people in the EU are on vacation, so out-of-office replies are common. More broadly, Apollo leads are definitely being milked—many creators have promoted cold email, so more people are using the same leads, increasing message frequency and raising the bar for good copy. As a result, your results suffer. This is typical competitiveness. To insulate yourself, find leads from other sources instead of just Apollo, which is an old database that caches Sales Navigator leads. Go directly to Sales Navigator, or combine it with other lead-scraping avenues like vain.io, or scrape the web yourself using tools like an appy scraper for Google search results, then use a mailfinder to get emails and decision makers. There are many paths to a profitable email campaign; Apollo and Amplify are just the lowest-hanging fruit, but if they're insufficient, you need to go above and beyond.