"...I still get the same error..."
..."has terminated unexpectedly during startup because of signal 6
This just says that it received a signal to abort (
, scroll down to Standard Signals)...
This is the most generic error code returned when a more specific one couldn't be returned, 'Unspecified' error...
(Microsoft's COM error codes
,Mozilla API error codes
...Virtualbox uses Mozilla's XPCOM)...
That is to simply say that, assuming you have a 'clean' installation above of the latest Virtualbox with no previous remnants,
the above error snippet, as it is, sadly, virtually tells next to nothing
as to why your Win10 VM doesn't start:
you should examine the whole Vbox.log
(Machine - Show Log
for any hints regarding what might have changed or goes wrong there.
If you can't figure out what happened by examining such (admittedly, Vbox's logs are generally quite a bit cryptic),
and don't wanna spend your time changing each & every setting at random until it works,
then save the log, & ask in the Virtualbox forums