I am sure that at one point a few years ago I tried an app for service for awhile that would automatically find time on my calendar and drop recurring todo’s that need set blocks of time into it. So for example you could tell it you wanted to work out 3x a week and needed 90 minutes to do so and it would watch your calendar and put them in there for you every week, working around events that were already in there.
Maybe my google-fu isn’t at full capacity today but I’m not finding anything. Does anyone recall this being a thing?