I've seen many blogs talk about using a Microsoft Converter utility, but the link is gone, and apparently was retired in 2016-2017 time period. I was able to export my Oracle VBOX (Virtual Box) using "Export Appliance" to a .ova (2.0) file. I also tried a converter from StarWind, but it didn't seem to be able to take an .ova as input.
I haven't used my VBOX image (of a Windows 2019 server) for about two years, and not able to get it working on my current laptop. I'm running Hyper-V on Windows 10.
(This is an article I was trying to follow, but it seems to be out of date: https://www.groovypost.com/howto/migrate-virtual-box-vms-windows-10-hyper-v/).