Not sure why people care so much about there being a plan, the vast majority of cinematic series never had a definite one either.
The difference is that even if its not planned out and something is being created as it goes along, there’s one person there guiding it along.
The OT while not all written strictly by George, was guided by George.
The MCU is being guided by Kevin Feige and they’ve had directors quit because they didn’t want to incorporate elements to setup and support future films.
The ST has no one, each director was left to do whatever they wanted with their entry. Kennedy is a brilliant producer but she doesn’t seem to have a vision for where to take the franchise.