No employee hardware is payed for by the business. We all use our own machines, and all three major operating systems are well represented. So in your opinion we're all ethically in the clear?
You're an employee in an enterprise, so I bet the following applies to you:
"TDF stressed that LibreOffice 7.1 "Community" is meant for individuals and that means specifically not enterprise organizations."
The license is free software and it would be suicide for TDF to switch the whole project to proprietary software. Therefore companies are in the clear and will likely remain so for a long time if not forever.
That's more aggressive begging than a mandate. They have a license for a reason, and that license clearly allows OP's use case. If they do not need the "business" level features Libre's partners offer I see no reason to upgrade.
Computers are semi cheap but this is still quite crazy to require employees to come with their own tools to be able to work. I'm happy to live in a country were employers have an obligation to provide that.
Ethically who knows but you're definitely legally in the clear
"definitely"? you don't even know what country they're in