Hi Antone,
Great questions indeed and I see how this could be confusing for sure!
Let me help to share a breakdown

Usually Starboard Pro models go through a 2 year model cycle so the models (regardless how good they are) get changed up. Race boards on the other hand usually go for a single year cycle and all round boards usually go around 5 years or so with maybe minor upgrades.
PRO As the PRO is designed for Team riders/competition primarily, it's important to have their feedback on the new boards.
Team Riders wanted the pro to be longer and faster, better in large waves and tuned for performance in hollow waves and critical turns. The 2022 PRO was designed as a great competition board for every condition whereas the 2023 model is more focused as a performance competition board especially in medium and larger surf, steeper turns, more critical sup surfing. 2023 Pro comes with Thruster fins.
SPICESpice range is the mid range between Wedge and the PRO. The Spice has great performance in all wave conditions and has a wider outline, more stable width and plenty of volume. It's designed for medium waves, clean conditions, choppy conditions and can handle larger surf. It is not as fast as the PRO or as critical but is more stable and has a different feel with great performance. Comes as a Quad set up.
WEDGEWedge is the intermediate range that replaced the Wide Point range a few years ago. Wide, stable and easy riding. Great range for progressing in SUP Surfing.
Pro vs Spice vs Wedge: