A lot of writing advice out there is... weird. There seem to be a couple different varieties. One is "first year university students do X too much, so nobody should do X at all!" This advice is usually "directionally correct" for many writers, but it shouldn't be taken as an absolute. The book Style offers better balanced versions of much of this advice. For example, it shows several examples of when the passive voice can actually increase clarity.
The other bit of weirdness in English-language writing advice goes back several centuries. There was supposedly an "arms race" of grammar advice, where each writer tried to ban more things than the next. The result of this was a bunch of rules that nobody has ever actually followed. Strunk and White is notoriously guilty of this. E.B. White was an excellent writer, but he routinely ignored the rules he proposed. Sometimes he ignored the rules on the very page where he proposed them! This kind of constantly-ignored advice is suspicious, because writing advice should ultimately be based on the common practices of well-respected writers, not on "zombie rules" that have been passed down for centuries without ever having been obeyed.
One good source for telling the "zombie rules" from the useful ones is Merriam-Webster's Dictionary of English Usage. This categorizes advice into rules that good writers actually obey consistently, rules which affect how formal your writing feels, and rules which have no basis in actual practice.
Weirdly, this tendency towards "zombie rules" may be less of an issue in other languages. For all that English-speakers love to make fun of the Académie Française, the Académie's grammar advice seems to be a lot more evidence-based, or at least focused on the well-established differences between spoken and written French.
In Matt Might's recommended reading section for that tool he points out Style: The Basics of Clarity and Grace by Joseph Williams, and reading that book and really learning a lot of things it shows will be much more helpful overall for your writing. Its use of contrasting examples is very effective. For instance, it shows how the passive voice can be a very powerful tool for controlling the flow of topics and ideas and actions in a sentence or paragraph. Through the passive voice you can improve the clarity and coherence of a piece of prose. As Matt Might says, it's about making it a conscious decision rather than to enforce all controlling rules.
I chose it over White's book because of this passage from Clear and Simple as the Truth:
> The best-known teachers of practical style are Strunk and White, in their ubiquitous Elements of Style. The best teachers of practical style are Joseph Williams and Gregory Colomb, in Williams’s Style: Toward Clarity and Grace and a series of academic articles and technical reports. Williams and Colomb present an incomparably deeper and more orderly treatment of practical style. The style they present is consistent and mature; it makes decisions about all the major questions that define a style, and is fully developed.
I almost can’t overstate how much it’s changed how I read and write. Before that book, some writing just felt “clear” and other writing didn’t, but I couldn’t explain why. Now it’s much easier to see how that sense of clarity is created. Even though I don't write for a living and mainly do technical write ups, it was easily worth the time investment.
This video is also good. It has a ton of interesting points, but the part about creating instability in your writing I found particularly useful.
https://www.youtube.com/watch?v=vtIzMaLkCaM&ab_channel=UChic...
Style: Toward Clarity and Grace
Style: Lessons in Clarity and Grace
Style: The Basics of Clarity and Grace
I can't speak to the first 2, but I purchased the 3rd and found it to be excellent.