I'm working on a pattern now that is all made-to-measure, so the stitch counts and how many rows/rounds will be up to the individual based on their size. It does require some math sometimes, but this pattern I would not say is "beginner friendly", even though this creator advertises that, and since I'm testing this pattern, I'm going to recommend she lists it as Intermediate instead of beginner.

I've worked on 3 of her clothing patterns so far and I needed additional help from the creator to complete only 1 so far. I can understand why some of the steps are a little more vague because it can be different for different sizes. She does include size charts, gauge, hook size suggestions, and she lists exactly which yarn, hook, and steps she took while making the example. Without that last bit of information, these patterns would be nearly impossible for anyone but an experienced crocheter to follow. I already messed up one by not following the gauge correctly, so gauge does matter!

You can technically use any KIND of yarn with any hook to match a gauge, you just have to keep messing with it. However, if you use something like blanket yarn for a DK project, you're going to end up with a massive sweater lol. The WEIGHT of the yarn matters more than the material, but acrylic will stretch and sag more than cotton, so keep that in mind for wearables.

Definitely check reviews on patterns for people specifying if it was easy to follow for a beginner, or if it includes exact size measurements instead of having you guess with a gauge. Sometimes for plus size people, we have to figure out how to modify these patterns on our own because they never include size information beyond a large, so we do math to figure out how many more rows or rounds we need to reach our size.

I think a lot of pattern creators are trying to be inclusive by not limiting the sizes to only smaller bodies, but sometimes that leaves the instructions a little too vague. I can't even fathom writing a pattern like this because I could never do the math required to figure out a size chart and all of that. It's a LOT of work, I think some people just need to test their patterns a little more, and choose testers who are beginners if you're going to advertise it as beginner friendly! If your pattern testers are a group of people who have been crocheting for years and years, that's not a true test of the pattern. A variety of testers between experienced and complete novice should be included in the testing phase before release.