Hi Turritopsis,
I have decided to uninstall the trial version of Microsoft Office Home
and Business 2019 (as it doesn't work anymore) and use LibreOffice
permanently!
That's great! Actually I use LibreOffice Calc in my daily work and there
is no big issue with interoperability. My best practice is that, for
local editing you should stick to the ODF format (i.e. .ods, odt etc),
and save a copy as xlsx or docx or PDF if you want to send it to someone
else who does not use LibreOffice.
By the way, does LibreOffice have the equivalent of Microsoft Outlook?
LibreOffice is an office suite and it does not bundle an email client
equivalent of Microsoft Outlook. You can use other email clients such as
the free and opensource Thunderbird.
Kevin Suo