Can anyone verify this translation for me?

[Devil Master]

Hello everyone. First, a premise: I know little Finnish, and what I know comes from playing Control and Alan Wake 2. I became interested in Finnish songs thanks to the presence of two such songs in those games ("Sankarin Tango" and "Yötön Yö" respectively). I've recorded a straight cover and a metal version of Sankarin Tango, I'm in the process of recording a metal version of "Yötön Yö", and I got the inspiration to record a Finnish cover of another song: "Agatha All Along", from Wandavision.

AFAIK, there is no Finnish dub of Wandavision, and in fact, I got the inspiration from a random mistake: first, I watched my own metal version of Sankarin Tango with subtitles on, then I watched my cover of the Italian version (yes, I'm Italian) of Agatha All Along... except that the subtitles were still in Finnish, and Youtube was doing the translation.
I immediately noticed how some of the lines kept the same rhythm and could be sung over the music, so, with the help of Google Translate, and a thesaurus to find synonyms with the right number of syllables, I compiled this draft for a Finnish adaptation of the song. Note that it's not a straight translation, because some lines come from the English version, others from the Italian version, and the rest is lines with the right number of syllables that are meant to give the same feel.

This is what I came up with:

Kuka aiheutti ongelmia?
Se oli Agatha, tietysti!
Kuka ei koskaan kyllästy pahaan?
Vain Agatha, tietysti!

Hän on ilkeä
Ilman armoa
Mutta kukaan ei ymmärrä mitä haittaa (haittaa)
Mitä? Mitä? Mitä? Mitä?

Hänen tekemänsä sotkua ei voida korjata
Kiitos Agatha
Tuhma Agatha
Se oli Agatha, tietysti!

Ja hän tappoi Sparky!

And the intended meaning:

Who caused problems?
It was Agatha, of course!
Who will never get tired of evil?
Only Agatha, of course!

She is nasty
And without mercy
But no one understands what's the harm (harm)
What? What? What? What?

The mess she made cannot be fixed
Thanks Agatha
Naughty Agatha
It was Agatha, of course!

And she killed Sparky!

I'd be glad if someone would please verify the correctness of this translation, and maybe offered suggestions to improve it.