I came across great method of testing your Blokada setup on Reddit today. Go to this ad blocker test site:
You can get a rating of how much your selected host lists are blocking and experiment with changing hosts lists or adding additional lists. With a few changes (using OISD, Goodbye Ads and Samsung Blocker) and adding one Google URL that the site showed was still getting through, I was able to achieve a 100% score with Blokada 4. A 100% score could break some functionality, but it’s possible if you want it.