Don't listen to that guide, it's from the same guy that posted one how nahualt caddo which is a horrible idea is overpowered .
First why not rush admin tech 5 and get admin ideas? They pay back extremely fast by removing 25% of the paper mana cost on coring and making land take 25% less time to get cored. It's quite unlikely to have enough paper mana to core enough provinces without them.
Second point, it's very unlikely for burgundy to not start with france as rival. And in case they have not you as rival at start not only it's very likely for them to rival you halfway through the playthrough (which can result in coalition) but they will be a very bad ally nonetheless by dragging you into bad wars or getting destroyed without player intervention.
Third point, allying scotland to invade england is much better than revoking guarantee. Just park your army there and dow england by calling them by land promise and don't give them anything as you don't care about the alliance.
Forth point is that there is no mention about spamming alliances with smaller nations to both lower the AE you get with them and to raise the limit on AE you can take before they are willing to coalition you. As france you can likely go for 10 or 11 alliances as most of europe loves you cause it's france, with the added benefit of disencouraging your punchbags from forming a coalition. Seeing how far you can push allies with AE while keeping the alliance is also a fun side game on eu4.
I agree that he makes plenty of mistakes, doesn't always make solid arguments and that this could have done a lot easier. Yet, I disagree with quite some points here.
- Getting admin ideas could work. no problem with that. I did that too. I would however, take influence first and rush the 4th idea which gives 20% AE reduction. With the state system, I indeed had no problem of getting enough admin points to tech to adm 7 and get core reduction cost.
- It's less unlikely these days for Burgundy not to rival you. If not, if you ally them and pull them into your wars,t hey are of invaluable help. No matter what you do, you declare war on England on 11 december right? Call them in for land and give them Calais which keeps them happy. Even if England allies Austria, which they almost never do anymore before 11 december, Burgundy will hold Austria off. They can drag you into some wars, but you don't have to do anything. They have a tendency to declare on the HRE, but hopefully by then, you're emperor. I believe they aren't able to declare on Liege that way anymore. Once you are emperor and have a royal marriage, you have an 80% chance I believe to get the double Burgundian Inheritance. In the meantime, you can feed them extra land, they will give back to you double cored the moment the inheritance fires. I had fed them parts of Provence/Lorraine later while I took Provence/Draguinion.
- I would revoke the guarantee on Scotland too. Not only because you'll need the relationship slots to become emperor but also to get an alliance with Castille/Burgundy. I usually go over the relationship limit as France, but keeping Scotland makes it harder to get all alliances. You don't really need Scotland anymore too. The war takes a bit longer, but there's a big difference these days in the first war with England. Pale no longer has a fort, which means you can demand it in peace deals. It means you border both Ireland and Scotland if you take it, which means by the time the truce with England ends, you can have a land border with them already after you've attacked Scotland. In the meantime, AE can tick down from the Portugese land you take. You can make Portugal a cobeligerent and at least take Porto and break all of their diplomatic ties. Once you core it, the rest of Portugal can be eaten for free, but make sure they do not renew their alliance with Castille.
- I sort of agree with your last point. I usually settle for alliances with Burgundy and Castille at the start. Once Burgundy is gone, I ally Poland while they hopefully still have Lithuania. If you're emperor by then, your forcelimit is nearly 75k already. With those allies, almost no coalition will ever dare to attack you.