Planner friends are not difficult, they need readiness
For some people, knowing the time, place, and structure in advance is how they organize energy, schedule, and emotional readiness. That is not pointless rigidity.
Spontaneous friends are not automatically inconsiderate
Some people invite you in the moment because that is how warmth naturally comes out for them. The trouble starts when that style always falls on someone who needs notice.
Long friendships need a shared rule for what can be spontaneous
A small agreement about what needs advance notice and what can stay flexible usually protects both people from reading each other unfairly.