Eat the cake and have it too*: I would say something more like "Eat the cake and keep it"

We who made the worst plan: In this case "värsta" is used in a positive way, like "we made the best plan", as suggested by the next row of lyrics Swedish is weird at times.

I remember like it was yesterday, but feels like it was so long ago: could be shortened to "..., but feels so long ago", helps with the flow

Sounds only like a bad joke: I would say "Sounds just like a bad joke"

I should have understood that already then: could be changed to "I should have understood it by then"

It starts easy, feels so right but always gets bad nonetheless: "... always ends up bad either way/nonetheless"

Or have you maybe blocked me?: "or maybe you have blocked me?" sounds more natural to me

you have either missed or forgot to translate the entire [Stick], whihc may be a decision or not, but just heads up!