Listened - interesting catch thanks! It's not a number station, and the phraseology doesn't fit a military network.
The transmission time is unusual, but I observed similar vocabulary (callsigns) and the way of driving (a woman in the leading station Handel 56) during civil defense exercises.
The Territorial Defense Forces have also been established in Poland - maybe this is their network because it is active around the clock?
At the beginning of the recording, 3 stations confirm readiness to receive - I do not hear anything about Russia there. Then the Handel 56 reads the telegram, the recipients acknowledge receipt.
The head office confirms the receipt of the confirmation, "end"
- - update 21 Apr. I found information about the preparation for Coalition Warrior Interoperability exercises in which the Polish Armed Forces of Territorial Defense take part.
This makes my assumptions more plausible.