I'm not sure Scholz talked much about Putin's motives (publicly) that early on. (There are a few snippets from the Feb 15 joint press conference with Putin, but Scholz doesn't start impugning Putin's motives to his face, then.) But surely by August Scholz did talk about Putin's motives more, as DW quotes/paraphrases him, recalling those Feb meetings:
German Chancellor Olaf Scholz has accused Russian President Vladimir Putin of launching an attack on Ukraine for "completely absurd" reasons.
"NATO was never a threat to Russia," he said on Sunday in Berlin during a public dialogue on the federal government's open day. [...]
According to Scholz, during the talks before the war started in February, he assured Putin that Ukraine would not join NATO "in the next 30 years."
However, Putin had "completely absurd" ideas, Scholz said. The Russian president told him, for example, that Belarus and Ukraine should not actually be independent states.
Olaf Scholz is certain that Vladimir Putin planned this war long before the Russian invasion of Ukraine began on February 24.
"This is a war that Putin, Russia, started, clearly with the intention of conquering its neighboring country. I think that was the original goal," Scholz said comparing Russia's actions with the early days of imperialism.
Russia is currently concerned with gaining territory in eastern Ukraine, but it is not certain that it will stay that way, the Chancellor said, so giving in is not a sensible strategy.
"Putin actually had the idea of swiping a felt-tip pen across the European landscape and then saying, 'This is mine and this is yours,'" Scholz said adding that Germany cannot accept that.
However, Scholz announced that he would not end the dialogue with Putin.
Possibly one of the earliest occasions on which Scholz talked about Putin motives at length was the "Zeitenwende [=watershed] speech" (as it was later called) that he gave on Feb 27, although that mostly references Putin's military actions and says little about their bilateral conversation(s), although some of Putin's catchphrases (from that Feb 15 press conf.) like "indivisible security" are turned against him:
The twenty-fourth of February 2022 marks a watershed in the history of our continent.
With the attack on Ukraine, the Russian President Putin has started a war of aggression in cold blood.
For one reason alone: the freedom of the Ukrainian people calls his own oppressive regime into question.
That is inhumane.
It is a violation of international law.
There is nothing and nobody that can justify it. [...]
The terrible images from Kyiv, Kharkiv, Odesa and Mariupol show Putin’s utter lack of scruples. [...]
The issue at the heart of this is whether power is allowed to prevail over the law. Whether we permit Putin to turn back the clock to the nineteenth century and the age of the great powers.
Or whether we have it in us to keep warmongers like Putin in check. [...]
With the attack on Ukraine, Putin is not just seeking to wipe an independent country off the map.
He is demolishing the European security order that had prevailed for almost half a century since the Helsinki Final Act. [...]
President Putin always talks about indivisible security. But what he really seeks now is to divide the continent into the familiar old spheres of influence through armed force.
The rest of the speech then mostly talks about Germany's response: decision to supply arms to Ukraine, more severe sanctions on Russia etc.
I'll add here a bit that I noticed today in Scholz's speech on sending Leopards to Ukraine (I'm not sure if there's a transcript published yet). Scholz used the expression "imperialistische[n] Angriffskrieg" a couple of times. It translates as "imperialist war of aggression". A quick google search also shows he used it in his New Year's Eve address, so I suspect it has become a somewhat formulaic expression that he uses to describe Putin's war/motives, in a nutshell. I haven't perused more of Scholz's speeches to see how often he uses that expression. It may have a bit of a Marxist connotation, or at least some other 1st page google hits are to such materials, so I also suspect it might be an expression deliberately chosen from that vocabulary, possibly to elicit support/sympathy from the more left-wing side of the SPD, which [IIRC] was traditionally more Russia/USSR friendly.
The expression Scholz used at the UN was slightly different--"blanker Imperialismus", which translates to something like "blatant [or naked] imperialism". (As noted in that piece, interestingly enough, Macron also referred to the war as an expression of imperialism, in the same venue.)