Are there any adhd friendly digital planners that do not steal your data?

So, I'm trying to get organised (again) and would like to try this digital this time, since my bag is getting rather heavy with my planner, note book for work, note book for private, whitebook and my other notebook and my notebook for that other part of work. I would rather not give all my personal data to elon musk or xi Jinping. No date outside of my personal device would be perfect. I tried obsidian but I seem to be too old and not have the digital skills for this. Just a planner with times and a calendar and an option to make and store notes would be fine. Does this exist? Thanks in advance!