Try to double boot Ubuntu 19.04 and Windows 10 legacy. (Windows 7 upgrade)

I'm trying to double-boot on Ubuntu and Windows 10; but since my upgrade from Windows 7, Windows 10 is in legacy mode. My initial problem was that Ubuntu could not find my Windows 10 installation during an attempt to install (I did not want to erase Windows 10.). that does not fit with my Windows 10 Legacy. Every search is basically the opposite of my problem (trying to get their install from Legacy to UEFI), I need help to make sure my Ubuntu stays legacy.

Someone has an idea? Am I using an outdated version of Ubuntu?