why did kernel wimboot gui fix my issue ?

[NiKiZe]

In my experience gui is always good, the only time you don't want it is when something does not boot.

I have been thinking that win10 boot.wim needs gui to work.

If we look at what wimboot does without gui it disables all VESA modes, which more or less forces text mode and lowest resolution. this might not work with never versions of windows or maybe it is new bios/firmware that is the cause.