I’ve not used the fedora installer, but from what I can tell you could try formatting sda6 with the filesystem you want and trying the installer again or maybe try clicking the + in the installer and see if it gives you the option to format sda6 and give it a mount point

Instructions for changing it here

https://wiki.archlinux.org/title/Firefox#XDG_Desktop_Portal_integration

Anyone that still wants a supported version of win 10, look into Windows 10 IoT Enterprise LTSC (2021) - supported until 2032 and can be activated by MAS with HWID