I never tried, but I think you can ignore the problem with GRUB, just keep it and set Windows as the default OS to boot with no wait (set the timeout to 0 or 1 second)
As for the rest, I don’t agree with you. The way the distros (with some exceptions) handle the installation of new software is pretty easy. Add some others ways like AppImage, Snap and the like and usually to run a new software you really just need some mouse clicks (and download time ;-) ).
And yes, the HDD are way slower than SSD. There is a reason why SSD are taking over HDD ;-)