The honest answer is probably yes, but you're in a fortunate position of being a high achiever, so you already know how to work hard and most likely are resilient enough to get through it.
More structured 6 forms often help lower-achieving students raise their grades and build soft skills as they bring the expectations up, it's often slightly trivial for higher-achieving students as they are more likely to be self-motivated and actively do all the right things. However, there are always outliers to this.
I also wouldn't assume all traditional 6-forms are more structured than college 6-forms, it can be vastly different from school to college.
I moved school for 6-form on an academic scholarship to a small private school and that place expected a lot from people. Everyone in the 6-form had to be there from 8:30-4:30, we had additional mock exams, we had individual mentors, expected to do 2 hrs of enrichment a week, 2hrs of volunteering and everyone had to do an EPQ, or at least start it. We regularly had talks with visitors, would visit different universitys, had career events, had to be involved with school events, do PE, first-aid training, life-skills classes etc etc. Though I wouldn't say any of this particularly got me into university, that was the hard work, the revision, working through holidays, being well-read etc. What it did do though was give people a work ethic so they could achieve regardless of their academic capability, even simple things like knowing how to talk to business leaders. However this could all be done outside of school, you just have to be actively thinking about your future. Every 3months think about doing something that you could add to your CV or talk about in your personal statement.
So to sum it up, focus on yourself, you are more than capable, so work hard and keep going.