Some of it is differences at college vs school-based, I know at the college two of my kids went to they ask permission of the students to give out any information to parents while it's largely assumed at schools; however, I have had two kids at the same college, different departments on different campuses, and basically had the same experience as listed in the OP.
DD in Animal Management, regular contact and details on parent events sent out regularly, I've met the tutors, we've had in-depth conversation on workload and on the work experience expectations and availability both during college years and if she continues into the HE department there. She finds 90% of her peers well engaged, though there are still the few students who hide from the practical work on their phones.
DS in Engineering, there was little from them, and you'd only know about the parent information evening if you kept tabs on the main college website event page. He had a lot of issues with the poor behaviour of others in his lessons, which was surprising for him and us as there was the idea that at Level 3 they chose to be there, but Engineering is one of those areas where at that level they can end up there on inertia if good at maths, particularly for boys, and end up dropping out. I think nearly half of his original cohort were gone by Y13.
Part of it may be department difference, some is programme differences (DD's requires 150 hours of work experience in the first year, DS's none required), and also DS was far less engaged himself compared to DD. DS would be unlikely to inform me if there was a parent's evening or anything similar. Even now, he thinks he's informing him of his leave and coming home by sending me a screenshot of his train ticket times, not getting that I might need more context.
I also had another DD who did an apprenticeship post-16, which had absolutely no contact.