The problem with all syntax-based writing advice is that it's an extremely poor substitute for taste, and taste has to be developed by years of sitting with prose, good and bad, and seeing what makes you cringe and what gives delight. If you closely read the expert writers and teachers of writing who purvey these rules, you find that none of them follow their own admonitions entirely. That doesn't mean the rules come from nowhere -- in this example, I have observed plenty of novice writers who use adverbs badly, so if you're trying to learn to write well, adverb-dense prose is a common sign of inelegant writing, and a sign that that prose might need some attention. But the solution is not "eliminate the adverbs at all costs" -- the solution is to read closely, feel it grate against your ears, and try revisions until it doesn't grate anymore.
Idk, I can get behind some of it as a mechanical exercise. When I was a young'n and honestly thought I was gonna be an english lit major one of my teachers made me go a whole year without using any prepositional phrases. Did that instantly improve all of my writing? No, in fact everything I turned out under that rule was clunky and overedited. But after that year any time I ran into a prepositional phrase that I didn't like I had the experience to know how to rewrite it effectively. The point is training, not product refinement. Find a device you lean on too much, eliminate it entirely for a while, and emerge from the other side of this process with a better understanding of the crutch, knowledge of several ways to work around it and wisdom to know when to do that. It's not a substitute for taste, it's a tool for developing taste and the ability to refine things to your taste.