Please help. Low AHI but still wake up all the time.

More likely than not those CAs are probably awake breathing flagged events and not real. SWJ
Not caused by pressure period.
Some central/CAs are normal and not caused by anything except normal causes even if they are the real deal. Like sleep onset centrals or sleep stage transitional centrals. When someone reports multiple awakenings...and thus multiple chances of going back to sleep then that also increases the chances of having multiple sleep onset centrals when one goes back to sleep.
These aren't bad...they are normal and as long as you aren't having a truck load of them...they are no big deal.
And you would have to have a LOT more of them to come even close to being numerous enough to cause a problem.

Higher pressures being a trigger for centrals...not nearly as common as DH wants to make it out to be and when it does happen we see a lot more of them than is seen on your reports.