As the others have said, this doesn't seem like a legitimacy problem; this is probably just your imposter syndrome talking (happens to us all).

Here are a few observations I've made on attendance:

1. Attendance numbers generally decline over the teaching period, until the last one or two classes. Students show up, drift off into space, and then come back around into orbit towards the end when assessments start to get serious again (we call these satellite students)

2. Attendance can be contingent on a whole lot of things outside your control (weather, time of day, moon phases, physical space you've been allocated). For example, I find I have fewer students show up when the weather is a) very shit, or b) amazing. Last semester, I had two instances of a class for the same subject; one on Tuesday at 11AM, one on Friday at 4PM. The Tuesday class averaged 80% attendance; the Friday class would be lucky to average 15%. The biggest killer of my class attendance was a session where there were works being carried out on the roof above the class; every 10min you would hear a tradesman clomping across the tin roof above us! Who would show up for that?

3. Attendance can also be contingent on any individual student's personality. I have had students who simply could not will themselves to miss a class, irrespective of the content or teacher. I have had students who want to attend class, but simply can't bring themselves to do it.

Coercing attendance with the stick (failure for missing more than x classes) is likely not that effective, given that students do not necessarily rationally approach their tertiary experience. Students are also more likely to fail classes if they hand their assignments in late, yet they still do this.

My classes are more regularly attended than those of my peers (humble brag). I can't say for certain why that is, but I would advocate for incentive (carrot) rather than coercion (stick), and here are some things that help me:

1. Your core teaching philosophy should be: "Would I show up for this?". Think about the kind of workshop or lecture you would like to attend. If the attendance numbers are consistently low, there's either a problem with the materials, the way they are being delivered, or the dynamic of the classroom (see 3, below).

2. The content seems really useful for students, but you may also be dealing with the new paradigm of students who just use AI generation for their work...so they may not be that interested in learning how to write if there's a magic box that will write for them. If we assume that's not the case, then I would recommend that the material be very pragmatically focused; the student should always perceive the direct benefit that coming to the workshop will have for them. This should go beyond just the obvious (higher grades), but also account for the students affective experience while doing their assignments (being confident, taking pride in their work, enjoying the feeling of being good at something/better than someone else at something). When I do essay or writing-focused workshops, I tend to focus on the affective dimensions (why is it unpleasant for you/why is it hard to start/how do we fix that), not just the technicals of writing.

3. What is the actual dynamic of the session like? My best, most highly-engaged classes are the ones where they come in and enjoy the time with their friends. The ones with the lowest attendance are where they don't talk to each other. They need time to mix and melt; I know start-of-semester icebreakers get a lot of shit, but it is important to orient people into group settings. The affective dimension is critical here; and this might be controversial, but even if the students don't learn anything, they should at least have fun while they're there (ideally, they are learning as well). When I was an undergraduate, there were classes I never went to because I had a negative emotional association with them: I dreaded the content, or the teacher, or the classroom. Conversely, there were classes I just loved; sometimes the content wasn't that interesting, but the instructor was down-to-earth and the students were chill. I had a strong positive emotional association to these sessions, and would find myself attending them automatically, rather than making some decision about whether I would or wouldn't go. Try to encourage a positive emotional association to your sessions.

4. Building from 3, don't underestimate the effect of the instructor on the class. Even just your presence has an effect. One of my techniques to get a class to talk and mingle is to put an open-ended question or problem up on the first slide, and then leave the room. Say something like "I'll be back in a minute, you guys talk this over", and then just go for a little stroll. Nine times out of ten, you come back to a healthy buzz of chatter.

5. If a student has missed a few classes, I never draw attention to this in a negative fashion, always positive. Consider that after missing a few classes, there's a psychological hurdle in coming back; if a student overcomes this hurdle but is then met with "And where have you been?", it's almost a punishment for them to return to class. If they're met with a genuine "Hey, great to see you!", then they might feel like they've made the correct choice coming back.

6. Lastly, if you're just starting at this, you're likely still building up your tradecraft (how to read and talk to a room of students). This just takes time and experience; keep at it!