I managed to filter that, geeksforgeeks.org and towardsdatascience.com out with Kagi. It's quite helpful being able to slightly reduce prioritization on a per site basis so that instead of showing up as top result it'll be buried a bit but still accessible.
uBlacklist can only block sites. But Kagi can raise or lower sites in pagerank, and can pin sites on the top. Boosting sites up in the result is more efficient than blocking spam sites one by one.