EVERSPACE 2

This can be achieved after the Dreadnought's side quest story line is fully completed.

From completing the repeatable encounter for the dreadnought, the crates that spawn have a change to drop equipment and weapons to have the Together We Stand set bonus.

Equipping 4 with this set bonus allows the Panzer Bomb (XR Bomb) to appear after defeating an enemy.

This set bonus is also available as a catalyst for Legendary equipment only.

I would suggest to grind out the dreadnought encounters until you have 4 different set pieces due to the cost of crafting the catalysts and you'll still need some pieces with the set found from the encounter.

Equip the set, kill any enemy and then shoot the bomb.

For this you will need four pieces of Together We Stand set that drops from Dreadnought events.
If you use this new catalyst like I do reload save afterwards to save resources.
Catalyst drops from Legendary High Risk Areas and locations of those from Incursions.