The dog-like enemies called "War Beasts" that players must fight and kill. In addition, there is an implied, but not explicitly mentioned death in the lore for Luna's Howl.
I clicked yes because Eris Morn, a character you interact with often, suffered a traumatic event where her fireteam was killed in a attempt to defeat a raid boss, Crota (as told within the lore). However, she never really displays actual symptoms commonly seen with PTSD. She is depicted as a very strong character who has the respect and trust of many of the other main characters. Sometimes this is described by characters in dialogue. In lore, characters sometimes will spend time bonding with Eris.
Due to the way weapons work in Destiny, flashing lights are a frequent occurrence. Certain auto rifles, such as Misfit or Arc Logic, can create flashing lights that can be painful for some players.
There are very rarely points when someone will be restrained by some sort of trap left behind as a part of a security system. The only time I can recall that someone was purposefully restrained by a person present is the Speaker in the cutscenes during the Red War campaign in Destiny 2. This campaign is currently no longer in the game and the cutscenes along with it.
There is no on-screen amputation in any way. One of the characters you meet, though, does have a prosthetic leg. There aren't any details given about how she lost her leg, she just has a prosthetic.
There is an entire enemy faction of bug-like aliens known as the Fallen or Eliksni. Another enemy faction, the Hive, utilize a lot of bug-like motifs such as worms and moths.
The raid boss Oryx, the Taken King is implied to be a transgender man in lore and is slain by players in the King's Fall raid in Destiny 1. While not explicitly shown, a lesbian couple perished in the Hellmouth on the Moon with the First Crota Fireteam. Their deaths are mentioned both in lore in both Destiny 1 and 2.