After teaching Credence magic for the past 6 months, Edward did not immediately return to the future, but observe how the changes he made would affect the world, and also discover how the power of fate works. So, without any surprise, things went to their original track without Edward's interference.
Grindelwald still escaped his prison in MACUSA, Credence still met and developed a relationship with Nagini, Queenie still became of the Acolytes. More importantly, Credence was still convinced by Grindelwald to join his cause in an attempt to use him to kill Dumbledore.
Even though he was already aware of his heritage, Grindelwald still convinced the naïve boy that Albus Dumbledore not only stole his family from him but all the glory that should belong to him.
As for Edward, he watched all these things from the comfort of his hotel through a glass ball using Divination. Although he wanted to see the confrontation of Grindelwald and Credence against Dumbledore, he did not want to wait so long.
He knew that this would be an interesting battle as Credence also broke his First Limiter through the power of the Obscurus. He might be the youngest person to ever do so.
According to his research, Credence's constant repression of his magical power allowed it to grow rapidly under the influence of the Obscurus; then, when he reached the limit of 25, the Obscurus broke through that barrier or Limiter for him.
Oddly enough, it did not break the Second Limiter. After experimenting on Credence, he also discovered the mysterious power that prevented him from breaking the Second Limiter. Under his guidance, he had Credence use his Obscurus to try to break that Second Limiter, but it was no use; no matter how much power is used, it was to no avail.
After that, Edward reviewed some memories he got from Nicolas Flamel. According to him, the Grand Alchemist used his stone to break the first Limiter. However, after realizing that the grievances in the stone were affecting his magical power, he did not want to use this method for his wife.
So, he studied another method to accomplish this task, which was a way for wizards to break the Limiter through natural practice and hard work. A method he taught to a young Dumbledore after the latter graduated from Hogwarts and met Nicolas Flamel and became friends.
Oddly enough, his method worked for his wife but did not allow him to break through the Second Limiter.
Edward then summarized his findings in this matter to research it later, but then decided to just ask Death about it. However, knowing how the latter operate, he knew that without a proper reason or benefit, Death would never give him such knowledge for free. So, he has to find a way to entice him.
Stolen from Royal Road, this story should be reported if encountered on Amazon.
---Scene Break--
Edward was floating in the air, invisible to everyone present, while a group of wizards listened to a man in the center giving a grand and motivational speech: this person was of course Gellert Grindelwald.
Edward watched how the events of the second "Fantastic Beasts Movie" unfolded without intervening. After Nicolas Flamel used a counter-charm along with other gifted wizards to save the city of Paris from the "Protego Diabolica Curse".
After that, he took out an Alchemy item and used it to activate the power of the Gate of World to return to the small dimension inside. After that, he returned to 1992.
As soon as Edward walked out of the Gate, he felt the power of time enveloping him and rapidly aging him by 66 years. However, before that power had the chance to act, the ring that Edward made before traveling through time released a temporal aura that protected him from the effect.
After a few seconds of constantly fighting this aging curse, Edward left his laboratory on the moon to start his grand plan.
--Scene Break--
An old man was standing in front of the garden watering his plants. Suddenly, some new memories that he did not have before appeared in his mind.
"I met Edward in 1926? Before he was even born? Is this rascal messing with time now?" muttered the old man.
Soon after, an old woman slowly walked next to him before saying: "Newt, did you just have a random memory of Edward in 1926?"
Newt just nodded to his wife Tina.
"So, what do we do?"
"Just ignore it. Edward knows what he's doing, and it has nothing to do with us," replied the old man calmly. Then, the two of them continued their slow-paced life.
Meanwhile, a few people like Queenie and Grindelwald also received similar memories. Aberforth received a memory as well, however, he did not know Edward's identity as he covered his face during their encounter.
As for the No-Maj Jacob Kowalski, he died of old age more than a decade ago--leaving his wife, Queenie, a widow.
--Scene Break--
After spending a few days going around the world, Edward was having dinner with his aunt, Amelia.
"You rarely take the initiative to have dinner with me, so what's going on?" asked Amelia calmly with a stern look on her face.
"Why do I appear so terrible in your mind?" replied Edward. However, all he received was a glaring stare. So, he went straight to the point of this meeting.
"I've had a recent change in perspective recently, thus changing many of my plans. I have decided to conquer the entire world and take control of the advancement of civilization on this planet."
Amelia frowned after hearing this, not because Edward's words sounded ridiculous, but because she was surprised by the sudden change.
The truth of the matter, Amelia is one of the closest people to Edward--even surpassing his parents at this point.
When he was young, because his parents were morally righteous people, she used to be one of the few people that he would talk about his dream of making the wizarding world into a very advanced civilization.
And Amelia never treated her nephew as a kid talking nonsense as she knew how talented and forward-thinking he was.
Unfortunately, after his parents' death, Edward stopped talking about his plans and developed some sort of deeply hidden disgust at the wizarding world. He entered a deep state of depression after that, and it was Amelia who got him through it; it was even her who gave him the idea of using magic to find a way to revive them.
Thus, when Edward told her that he was moving forward with his plans again, she was indeed quite surprised.
After taking a moment to ponder about his words, she asked: "What do you need me to do?"