I find this a little weird honestly, but there should be an option to receive a notification for when an activity (such as farming) finishes? There's so many timers in this game, without a good system for checking on them - a timer page would be good too and I've supported a suggestion on that, but I'd also like to receive notifications when something finishes. If a timer page was implemented, it would be nice if this was where you could access the toggles but otherwise I imagine it'd just be a small button or toggle at the top of an activity page. “Notify me when this is done” etc etc.
It's a very small feature, but I think it'd be a pretty helpful QOL feature to have in place! I looked around, and it truly doesn't seem to be an option, so y'know it'd just be nice to have.