When did Germany peak after the unification?

Hi guys. I spent two weeks in Germany last month and after having interacted with a few locals, I have a question. When did Germany peak (in terms of economy, society, education and cleanliness) after the unification?

I ask this because while I was traveling by train from München to Köln, I met a German couple who sat next to me and since they spoke a little bit of English and I spoke a bit of German (I studied in Germany from 3rd to 6th grade), I asked them how they were doing today. And oh my lord, did they start complaining about EVERYTHING, from the trains, cleanliness of the cities and how corrupt the government is. They even complained about how fries at Frittenwerk got more expensive than last year.

A few other locals I met also complained about Germany becoming worse and worse.

I was surprised that these guys complained about things more than me, a 17M from India, a place where corruption exists EVERYWHERE🤣

So, when did Germany peak after the reunification?