Spark looks cool. I'll test drive it myself, thank you!
I got onto Canary when it was Free Download as well, they only started charging later. Let's see if Spark can remain free.
I am sorry to ruffle feathers. Please accept my apologies for wasting your time. I won't go any further into disputing your suggestions.
Mail was a hassle for me - Canary works. I am not affiliated with the developer and I was searching for Mail alternative for months.
I understand it. Mail suffers from iTunes syndrome - Apple trying to re-invent a workflow/UX for the sake of differentiating themselves. At the same time it manages to clog the system drive with it's uncompressed, badly indexed mbox store. Poor programming + clumsy UI = bad software.
The model for Linux is different than the paradigms used for Windows/macOS. The onus is on the distro maintainers to offer correctly configured packages of your software for their distro. If the distro does not bundle LibreOffice then it is not for the user that seeks it and they should look...
You should enable the 'powersave' or 'conservative' cpu frequency governor, either by compiling it into the kernel or loading the module, depending on your distro. Also the choice between Intel P-States driver and ACPI CPUfreq driver can affect power consumption...