Good mail, calendar apps

One thing that I love about MacOS are the fully functional, richly featured free first party apps for all the basics. Mail, Calendar in particular. I find this lacking in windows. Outlook doesn’t feel satisfactory and searching for third party solutions is the only option.

Are there any great mail and calendar apps? I don’t mind a one time purchase but would like to avoid subscriptions.

Priorities: 1. Multi account support 2. Pretty UI and UX 3. Optimised resource consumption