Those kv values are recommended motors, not limits.
When an esc does have a kv limit it has to do with how many times the phases switch, and a 4 pole motor switches twice as much as a 2 pole motor. So if it had a limit of a 3000kv 4 pole, it could handle a 6000kv 2 pole.
Your 6.5 is a 2 pole, so no worries
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It's "Dr. _paralyzed_" actually. Not like with a PhD, but Doctor like in Dr. Pepper.