Haven't had any experience with eweka, but this is the reason why people tend to have multiple providers from different backbones and multiple indexers - to increase your chance for completion. Weirdly, eweka does not follow DMCA, but NTD which I've seen regarded as slower to take down content, so in theory the experience should be better, especially on fresh content.
Your mileage will vary greatly depending on what indexers/providers you pick and unfortunately it's very difficult to say whether it will reach your expectations until you try different options.
If you're willing to spend some more on it, you could try just looking for a small and cheap block account from a different backbone to see if it helps with the missing articles, but there are no guarantees.
