I want to shill Horizon's Gate.
https://store.steampowered.com/app/1224290/Horizons_Gate/It's part tactical RPG with your usual FFT-style mix-and-match classes and skills mixed with open seas adventure exploration. The overworld map can only be traversed via sea/river, with the in-game locations being on land. You can explore the coasts of the world looking for dungeons or towns or whatever to explore with your crew, be a merchant and buy goods from one part of the world to sell elsewhere, do missions for factions, be a pirate and attack independent merchants or entire national fleets, etc.
The ship combat (which is also tactic rpg-like) is really fun. You can sink ships normally (each ship has different stats & you can gear them as you like), or if you get close to an enemy ship, you can board them with that ship's crew (which might not necessarily be your A-team units) & try to take out their crew (with a turn time limit that'll kick you back to the ship tactical rpg fight, but preserve the enemy crew's injuries) and take the ship itself. Each ship has a unique boarding map, too.
The major downside is that there is zero story and it is a genuinely open-world game. You're given a tutorial, and then all but told to fuck off to build your crew/fleet until you're ready to do the ending. The grooves (one of the more common dungeons you can find on the world map) are very short, & there are only a few proper dungeons, so you might be hit with the opposite end of the "wide as an ocean, deep as a puddle" spectrum. Mods help quite a bit, but it's pretty easy to feel like there isn't enough proper content to justify how developed the mechanics are.
