It might help if you see those kind of things as tasks you want to do at a certain time instead of it being appointments. I’d consider appointments something that isn’t actionable at all, it is just something where I have to be at a certain time and that has a certain duration. Tasks would go in app such as OmniFocus, appointments in Calendar. You can set defer date/time so you will only see them when they apply (=when the set defer date/time has passed). By using the Forecast view you can see both your tasks and appointments for that day/week. You can add notifications to the task as well so you are alerted in time (thus no need for setting a due date).
On macOS going from an entry in Apple Calendar to OmniFocus can be done by selecting the calendar item and copying it (rightclick > copy or use cmd-c). If you go to OmniFocus, create a new item and hit paste, it will at least paste all the info from the calendar item. You do need to put the information into the right boxes in OmniFocus. There are 3rd party calendar apps that integrate with OmniFocus and make this a lot easier. Calendar on macOS doesn’t seem to support the “send to inbox” option that OmniFocus creates in the macOS Keyboard Shortcuts. This option does work with Safari.
On iOS your only option is to use 3rd party calendar software. The in-built doesn’t do things like this, it even doesn’t use the share sheet (same with Mail). Hopefully that is fixed in a future iOS version.
That said, there is another option that can get quite technical quickly. OmniFocus (as well as other apps from Omni Group) offers support for automation. For OmniFocus automation there is even a dedicated subforum here and there is also a dedicated website for it: https://www.omni-automation.com (not sure if this is from Omni Group though).
To repeat tasks you can do so via the Repeat option found in the tasks properties. I use this for things like my medication. When I check it off, it will automatically create a new item for the next time.
Do keep in mind that OmniFocus is not project management/planning software. For that you need to use OmniPlan. OmniFocus is only for managing tasks (folders, projects, subtasks and tags are only for organising tasks).
For learning OmniFocus there are many resources. Omni Group offers their own: https://inside.omnifocus.com
