SnickerShroom

First of all, Blackarachnia and Arachnus are not same. Blackarachnia was known for her scientific knowledge and her influence on Blitzwing in the 2 or 3 season, Arachnus would not have done such a thing to Blitzwing. This is more related to his character. Even in his terrible form, he would not torture or exploit anyone for his own benefit, which is why Optimus saved Blitzwing and did not harm him in any way while helping the Decepticon.

Optimus's character after his transformation into a spider should not affect his character, as in my AU, he went into the hole on his own initiative and allowed Elita-1 to escape, but he paid the price for it. Thus, they had an unspoken alliance, and thanks to each other, Blitzwing was able to report on the help and the abandoned ship with a large supply of energon.

Thanks to the help of one of the Decepticons, Optimus's techno-organic body, which cannot be detected by sensors, his mastery of weapons, particularly the axe, and his strategic thinking, optimism, and ability to improvise, Megatron recognizes his potential and invites him to join the Decepticons. Optimus, unable to leave the planet in any other way, decides to take this step, which will have a significant impact on his future.

[I know, I've been holding this up for a long time, I'm sorry, honestly! In my defense, I can only say that I haven't had the desire lately, and one of my things broke down, which finally buried me deeply. And all the early posts were pre-planned. But I hope that you will forgive me and that I will be able to draw more about them!]