Is having different apps for different things something you see as a problem? There are apps that try to do email/calendar/tasks in one app, but they tend to be optimised for a particular ecosystem (e.g. Outlook or Nine are designed for Microsoft environments - Nine certainly can handle non-MS email but doesn't do the calendar or task integration with other accounts). But knowing whether this is something you want, or whether you are happy with different apps for different things (which is how I work by choice) may make a difference to the answers.
There are many more apps that integrate calendar and tasks but don't do email, some that copy the old PDA PIM tools and also include address books (Informant comes to mind, if that still exists - I've not looked at it for years, never really worked for me).
Personally the pandemic hasn't made much difference, since I've worked online for decades. But I've also never felt the need to integrate tasks or calendar with email, and since I work in large, multi-organisation teams who all use different mixes of systems calendar/task sharing tools have never been much use to me: I just use email to organise things, nothing more. So I don't know that I'll have any tips that will really help you (especially since I never got on with task lists, so still just do that sort of stuff in my head - I've several apps, but in practice I don't use them. Calendars, on the other hand, I use in a big way).