Rail Pass or Station to Station???

Go over to trenitalia.com and do it yourself. That way we don't have to show off our knowledge or experience. With you limited train travel the pass would be waste of money. If willing to lock into a schedule some of those tickets would be available at discount but discount tickets cannot not be changed or refunded. Standard walk up ticket (Base) are pretty cheap so I would be to concerned with discount tickets in Italy. In Rome it is the train, Leonard Express, to the airport -- 2 times a hour, 35 minutes.

Point to point
Rail pass never really useful in Italy

Bologna alllllllll the way down to Amalfi,

There is no train in "Amalfi"- so I assume your train ticket is to Naples or Salerno? You will then need to travel onward via bus, ferry, private driver.
Exactly where in the area are you staying? Amalfi town? somewhere on Amalfi coast?

All you need to know about train travel in Italy:

https://www.seat61.com/train-travel-in-italy.htm

Read thru above link then come back with questions

I won't show off so just mention Italo

Currently I have a one way booked from Bologna to Amalfi on highspeed
rail,

Same as above: there is no rail line to the city of Amalfi so I'm curious what you've booked, and through which website? As Christine mentioned, it may be to Salerno, which is at the farthest east end of the Amalfi Coast.

I am still not showing off, just to remind of the reservation fees for every leg of train travel if using a Eurail pass in addition, everything above RV, and not on Italo

I wish I could address you all individually, but in short, YES, correct. I am coming to Napoli Centrali station, and do have a food experience booked in Piarillo, right near city of Amalfi.

So, in this scenario, I'm looking for best transportation experience from Naples to this location, I'm thinking a coastal train ride, but have also seen some commentary on the Ferries, but do not know which, plus would still need a connection to Piarillo.

Any advice on this particular leg is much appreciated.

There is no train along the Amalfi Coast

Can’t find anywere called Piarillo-are you sure of that name?

Train to Salerno will get you closer to Amalfi
From there ferry, bus or driver are your options
Easier/quicker than from Naples

I'm a dummy, it's Pianillo, inland of Praiano.

Ok
There is no ferry in Praiano so your options from Amalfi are bus or driver

Bus schedules for the area, don’t see Pianillo listed-I’ve never heard of it
https://www.positano.com/en/bus-schedule

Are you staying in Amalfi? If so you might ask your hotel how to get to Pianillo
Where did you book this “experience “ maybe that firm can advise how to get there

There is a lot of good info on the Sorrento Insder site
https://www.sorrentoinsider.com/

SITASud is the bus company
https://sitasudtrasporti.it/campania/biglietti-e-abbonamenti

Brian-

For us to give you the most accurate advice and info on transportation it would help if you tell us exactly what you are planning

Give us your complete itinerary-where you are coming from and going to, dates, where you are staying etc

Transportation in the AC area is chaotic, crowded and often unreliable and always time consuming
The ferries may not even be running yet-we don’t know what your dates are
Ferries are always weather/sea condition dependent as well

There are many threads here discussing these issues-worth your time spent searching the forum and reading thru
Filter your search by Type and Date

Looking at Google maps shows that Pianillo is served by bus 5080 from Amalfi- operated supposedly by this bus company- https://sitasudtrasporti.it/

Amalfi coast transportation is when I just take out my wallet and pay for convenience. There are a million transportation companies and private drivers, because the public options are pretty bad/inconvenient.
Companies often recommended are Joe Banana and Aldo Limos, and there are private drivers, all which need to be arranged in advance, but you could just take the train to Salerno and then take a taxi from there. Bring cash - the further south you go, the less likely they are to want to accept a card (even though they are supposed to) and make sure you agree to the price in advance. Last time we took a taxi from the train station in Naples, we paid a hefty "tourist tax" (my term for being stupid and getting gouged).

Edited: It's further than I thought from Salerno to Pianillo so a taxi on the spot might not work. It really would help to know more specifics of where you're staying so that we can give better recommendations.

Edited again: Coming into the Naples station, I'd just pay for transport. But I have more money than time at this point in my life.