Again, how was Sage a good/well-written character? You can't call someone "the smarter person on Earth" and then all that she does is come to you and say "see, this is exactly what was going to happen, the plan worked!". Remove her and you lose nothing.
While I understand your frustration with Sage, as it seems like the showrunners are leaving intentional blanks for a big reveal later. I just wanted to point out below the things she did that Homelander would not have done, as it would go against his character.
Here's what Sage did, confirmed:
-Sage fueled the chaos between the Starlighters and Homelanders with planted bodies and starting a riot/brawl, forcing higher parties like President Singer to take action and making Starlight take a backstep. (It's possible Homelander could have done this, but it probably would have been through a media push alone, no setting up of dead bodies or anything like that).
-Sage pushed for Ryan to have space and be alone on his own journey when Homelander wanted him to be a coddled sidekick. (Homelander would not have done this)
Whether or not this would have always led to Ryan going down the path he went is unknown. It's clear that at this point Ryan does not like either of his father figures.
-She used the selfie in the above scene to recruit Firecracker who wanted to spread her messaging and propaganda to the largest stage and audiences, fueling the above chaos even further, because Firecracker had a grudge against Starlight from her past and would do whatever it took to bury Annie's image. (Homelander would not have personally recruited Firecracker as she would have been a useless supe in terms of power, nor would he have even went to that convention in the first place)
Firecracker was successful in doing this so Annie is no longer a bastion of good intent, publicly. Starlight's campaign building is in shambles and most of her workers have left after the scene of her snapping. She lost a huge amount of momentum she had going against Homelander.
-She appealed to Neumann's disdain for the people pulling the strings, even using the 'little girl' line to appeal to Neumann's want for her daughter to not grow up in the same conditions she did. It strengthened an alliance for a person who Homelander/Sage would benefit from whether alive or dead, by attempting to relate to her. (Homelander wouldn't do this and would instead go for the usual 'force/threaten Neumann to do it' as seen in the finale when he loses his patience, causing Neumann to flee or go to The Boys much sooner than intended).
-Sage was the one who suggested hiring the January assassin/shapeshifter to Homelander and he greenlit the idea. The assassin successfully infiltrates The Boys' group through Annie. Thanks to this, there were two ways to win. The first way is by using Annie's image to take out Singer. The other was the recording and the assassin was able to record the conversation of Singer asking about The Boys' progress on killing Neumann. Assassin is presumed to have sent the footage while getting water. (Unclear if Homelander would hire an assassin, as his methods have been very upfront, direct, and brutal and old Noir was sent out in the past by Stan).
-By continuing with her plan even after being fired and leaking the video, she has gained Homelander's ultimate trust without the need for using convenient distractions like breast milk.
Here's what is unknown:
-Why Sage was in the library next to Tek Knight's lair door. Was having Neumann speak on behalf of Homelander in order to publicly show that the two were in solidarity, on purpose?
-If Sage actually saved A-train's life with a misdirect and stall on identifying the leaker to Homelander. She knew it was him by the time they had the press conference about their new Marvel-esque timeline of Vought movies, maybe even before that.
-What was actually in the notebook that she left and came back to pick up?
-We don't know what happens after the document was given to the guy in the street by Sage (which was presumedly not the assassin, just some guy as a misdirect so that A-train would take pictures of this to warn The Boys) and the assassin/shapeshifter is found hiding in a closet afterwards from The Boys' perspective. That seems like an odd way for someone to be found, and it doesn't seem accidental.
Remove Firecracker and you lose nothing.
I listed moments above that justify Firecracker's involvement.
Remove the new Noir and you lose nothing.
This, so far, I agree with almost completely. He is being used as a joke character right now so I don't have much to say about him. I feel that he is going to be pushed even further into the background as we get pretty big returning characters and a brand new character played by Supernatural's leading co-star.