Phantasy Star Portable 2 is the best for a faster paced loot ARPG. If you like games such as Diablo where loot is a big component of continued play or you just want something faster, this is the way to go. Both Portable games are worth a shot though, dozens of hours to spend on each even as a solo player and if you're on emulator I know there are people who play together online. The Infinity expanded version also has an English translation now!
Monster Hunter Freedom Unite and Portable 3rd are also must-mentions. If you like crafting systems, cozy vibes, low fantasy settings and slower combat than that is your bag. Tons of variety in setting, weapon types and enemies to fight. Pokke Village in Freedom Unite is probably the coziest area in any video game for me, everytime I hear its theme I almost tear up because it just feels like home.
If you want something isometric then you have the Untold Legends duology. They're pretty basic as far as the itemization and skill tree systems go but they control solidly and have decent stories worth experiencing. You can beat em in a weekend of casual play and if they really click with you running through the campaigns in NG+ to minmax your build or trying other classes will be a solid way to spend some time. I liked the second one a lot back in high school but I've struggled to return to it. Also note that on original hardware both games have some framerate issues but for the most part its nothing game breaking.
Now, all of the above games are great fun solo but were designed for multiplayer. While on emulation multiplayer is possible for some if not all of them I assume you'll be divin in alone. If you do want more strictly single player oriented games, the Ys series is the obvious choice. There are like 4 or 5 Ys games on the system and they're all fantastic. Falcom is known for weaving simple yet enthralling stories with solid writing and fairly short length for an RPG and none of the PSP entries disappoint in this regard. My favs are Origins and Ys 7!
Honorable mention to the Rengoku duology. Very solid games with an intriguing setting. Recommend the 2nd one the most!