Pillars get dismissed as marketing-speak, which is a shame, because the underlying idea removes two problems at once.
What a pillar actually is
A recurring type of post you make repeatedly, defined concretely enough that you could brief someone else to make one. Not "educational content" — that is a category, not a pillar. "A two-minute video answering one question a beginner asks me" is a pillar.
Four or five is the right number
Fewer and your feed gets monotonous. More and none of them become recognisable. Between four and five, each one appears often enough that your audience learns to expect it.
Why this fixes tagging
Each pillar gets its own tag group. When you sit down to post, you already know which pillar it belongs to, so the tags are chosen before you start. No improvising, no reaching for the same twelve tags, and your analytics become readable because posts group naturally.
How to find yours
Look at your last fifty posts and sort them into piles by what kind of thing they are. The piles are your de facto pillars. Keep the ones that performed and that you enjoyed making; drop the rest.
The unexpected benefit
Pillars make batching possible. Filming four of the same pillar in one session is dramatically faster than filming four unrelated posts, and the quality is usually better because you get warmed up.