After inspiration from Foxl, and after a long, often painful 2 months, I have finally painted the world red.
However, I did use some cheats since I am an impatient person:
I used the occupation bug so I wouldn't have to wait for months, or even years with level 5 forts to occupy provinces
I eventually removed the Jingoism requirement for adding wargoals, since it went up really slowly(and in fact prevented me from getting all of France's colonies in one war)
I reduced the diplomat travel time to 1 day so I could add wargoals quickly
I doubled DP gain around 1910(while fighting China), which was compensated in the late game where I often sat for 1-2 years at 9 DPs since I had truces with every other country
In the early game, I was failing against France, so I had Prussia and Italy DOW them; however, I eventually conquered Spain and easily defeated France by stacking African troops there, so this cheat didn't really help me much in the long run
Minor cheats:
I tweaked the probability for realist literature so I wouldn't have a 0% chance of getting it just because I discovered realist art
I deleted most of the events around 1920 to reduce lag
I tried reducing MTTH for gaining cores to 1 month, so I wouldn't get spammed with these, but I didn't notice any difference
Mods: I used the GTFO mod so that I could conquer my Indian puppets and Burma
I passed all the reforms and researched all the techs. Lag prevents me from continuing, but I bet I could get all the inventions before 1936. I have turned most of my colonies into states, except a few in Africa, India, and China. The World is about 20-25% British and has 2 billion people.