@otter my notes are in Obsidian with Syncthing syncing, but my productivity and todo management has been in paid TickTick the last year. On average I have about 100 - 110 open tasks at any time. Many are monthly, quarterly, annual or longer repeating tasks like licence renewals, weather station maintenance, etc.
My tasks are all grouped into home maintenance, my mom's stuff, medical related, radio related, server related, etc. Most have dates set with reminders, and many also have sub-tasks to be completed. I keep detailed notes in each on progress etc.
They sync across my Android phone, iPad, Linux desktop. It's a bit of work bit brings piece of mind as I don't worry about forgetting to do stuff.
TickTick was my best choice based on about 7 criteria I compared for my needs. Unfortunately, Google Tasks and others I tried were just not working for me as I needed multidimensional views. I like that I can snooze tasks from any device, or drag and drop to a new date, etc.