I have been bitten by QNAP its underlying system so I can no longer recommend them.
What I can recommend is TuerNAS scale. It is not hard or complicated as some might make you believe. The ui is so much cleaner and easy to navigate then the more desktop style UIs.
Only device meeting the requirements. One of the only devices which allows relocking the bootloader. So it is a matter of no other alternative existing
Ask him which software it is that requires him to run windows. If it can not be used with wine their is also winboat. Which is technically a windows VM where programs seemingly integrate on the Linux DE
Euh depending what you get. Don't be fooled by their "ZFS" offering. It is a very very outdated and forked form of ZFS. I converted to TrueNAS scale with my qnap recently. Worked great. Although some things you have to do a rather advanced for more casual users.
I have been bitten by QNAP its underlying system so I can no longer recommend them.
What I can recommend is TuerNAS scale. It is not hard or complicated as some might make you believe. The ui is so much cleaner and easy to navigate then the more desktop style UIs.