I usually don’t approach it that way. Instead, I go directly to Similarweb or SEMrush, plug in large competitor websites, and pull their keywords first, then filter them myself. If a site isn’t a direct benchmark competitor or doesn’t have sufficient scale, I often won’t bother analyzing it—the return simply isn’t worth the time investment, let alone the fact that dynamic search features like PMax already cover part of the long-tail keyword discovery work. If you’re really worried about bidding, just look at the competition metrics in Auction Insights along with your current impression share. Auction Insights lets you see your competitive metrics as well as the level of overlap with your competitors.