Russia Ukraine war, page-38180

IMO, the "fight" was over in a little over 2 weeks, not 5.

The German Blitzkrieg doctrine was aimed at avoiding points of resistance (i.e. fortified, or entrenched, defences) and targeting vulnerabilities, such as the enemies supply lines.
Therefore, sieging cites would be avoided, in favour of capturing ground.

You cannot supply a city if the enemy has surrounded it; if you cannot resupply it, it will only be a matter of time before the city falls. (e.g. Mariupol)

The Poles were simply overwhelmed by Blitzkrieg strategies, and their allies failed them in their hour of need, which is why they had no choice but to capitulate.

Yet, somehow, you offer this as an example of success.