I have a 2016 1801 with same year F115 Yamaha, owned since new, factory (black stainless) prop (don't have the size handy). From the factory, motor would ventilate (aka cavitate) too easily, and was a tad slower than expected to get on plane, even given considering the conservative hrseper. Then I noticed the motor was mounted quite high (anti-ventilation plate was about an inch ABOVE the hull's keel, rather than an inch or so below as per Yam manual). The dealer lowered the motor one mounting hole (about 3/4", so now there's only one open hole above the top bolt) and it helped tremendously - ventilation very infrequent, and the motor's trim range is where you'd expect - at proper running angle, you still have at least a few bars (on LCD guage) of downward trim range available, eg to "put the bow down". Even though the ventilation plate is still higher than Yam manual suggests. Still, in seas >2', I have a hard time finding a good running angle that will both keep the boat on slow plane, yet keep passengers from getting soaked. I can use motor trim to put bow down, but then she throws a good deal of bow spray that a crosswind will blow back into the passengers. I do NOT have trim tabs (which many have suggested will help Parker's modified-vee hulls - eg the 1801 and the SE series), but not sure it would as I can already get the bow down using motor trim - the root cause seems just not enough deadrise midships, the hull's primary running surface at slow plane. Though perhaps lowering motor to the final hole would help improve some other unforseen dynamic going on - open to suggestions.
I would check your mounting height, and also confirm your motor is making full power (ie for holeshot concern) - eg any change recently, as in after winter storage / ethanol clog injectors.
