Destiny 2 Into the Light has introduced a new seasonal event, Onslaught, which comes on strong making it a struggle for players, with high enemy densities, Power delta, and various modifiers making this kind of event quite a pain in the second half of the match, and it may be difficult for most players to complete all 50 waves of Onslaught in Destiny 2.
 
With such a demanding endurance test, there are two things you need to focus on to win all 50 waves of onslaughts in Destiny 2: building and defense. Whether you're in Regular or Legendary mode, the only way to make it through 50 rounds of onslaughts is to build killer structures and Get Destiny 2 Silver by the best defenses.
 

Build Decoys
Of the three optional defense types tripwires, decoys, and turrets, Sweeper Bots play the most powerful defensive role in Onslaught as decoys. They can attract the attention of all non-destructive enemies, have a strong lifestyle, and are relatively inexpensive to manufacture. While they cannot sustain attacks from explosive enemies, a Decoy Sweeper Bot can often single-handedly save the ADU from a rogue Tormentor or Champion.
 
Build at least one sweeper bot for each ADU objective and place it closest to the key point blocking point, be careful not to build too many decoys, and make each one play its important role, the best way to build is to upgrade a sweeper bot and make it sturdy. If the player completes the above suggestions, then they won't have much of a problem defending in waves 30 and beyond.
 
Throw Your ADU Cores At Defenses
One thing that many players may not be familiar with is that you can repair defenses by throwing ADU cores at them. This action does not deplete the number of cores and emplacement quickly restores most of the HP. In the later stages of Onslaught, especially on Legendary difficulty, it is crucial to keep decoys alive. Therefore, it is a wise strategy to keep a Core at the end of each wave and use it to repair defenses.
 
Use Your Heavy Weapons
Players need to use their heavy weapons in the game, and machine guns are the ideal choice, perfect for players to clean up ads and Tormentors. You can use a Heavy crate that spawns near the ADU and interacting with it will completely restore your ammo.
 
Vostok is The Best Map for Wave 50 Clears
Guardians need to actively defend your ADUs on three different maps, each with their  advantages and disadvantages, e.g. Midtown traffic jams but Spawn points are close to the objective, Vostok has small chokepoints of open space and is relatively simple, and Mothyards bonus objectives are troublesome.

Play On Vostok
Saboteurs: The Fallen employ Marauders, swift and cloaked adversaries known for their remarkable speed. The Hive deploys Knights.
Explosive Units: The Fallen deploy Explosive Shanks, impervious to critical hits. The Hive unleashes Cursed Thralls.
Furthermore, Explosive Shanks often come accompanied by Heavy Shanks, recognized as one of the most resilient enemy types in the game.
Disarming Mines: The Fallen protect mines with Brigs, adversaries immune to precision damage for the majority of their HP. The Hive utilizes Ogres instead.
Be cautious, as contact with the Brig's faceplate can result in instant death.
 
Buy Destiny 2 Silver Build the best defenses, the best buildings, and a strong fire team and you will win 50 waves of onslaught. Now, can you do it on Legendary difficulty? Good luck, Guardian.