I use this site sometimes to find cards that are similar to one another. It’s automated so the comparisons don’t always fulfill the same role but it’s usefully different from lists that are curated by hand like https://www.mythicspoiler.com/. mtgassist.com has a similar feature but I prefer the results from Card Codex.
Compare the results from these two links
https://cardcodex.com/?card=Urborg%2C+Tomb+of+Yawgmoth#search
https://www.mtgassist.com/cards/From-the-Vault-Realms/Urborg-Tomb-of-Yawgmoth/
The model certainly has some obvious flaws like you noticed with Dynamo and Powerstone. I don’t think it “counts” words or symbols on cards and it definitely doesn’t have a notion of the “role” a card might play in a deck other than its key words.
I like using it when I have a card that has a niche intersection of mechanics/words and I want to find all the cards that are as similar as possible without manually searching every possible subset of those mechanics or words.