TL;DR - PSO Is great if you love grinding. If you are going to play PSO stock, play the Gamecube version PSOvI&IIPlus (it has more quests available for offline play than the original and is the definitive version to play by pretty much every PSO GC player). If you wanna play on PC online with friends Ephinea PSOBB is honestly the only server worth playing on.
It's a damn shame your first experience with the PSO world was with the god forsaken PSO2 New Genesis update... I can see why you didn't click with it. The only people even playing that game now are people suffering from the sunk cost fallacy. NG actually ruined PSO2. It's one of the few times where I hope the game finally goes offline so that a certain
Team (hinthint

) can put out their old school PSO2 private server that they've basically got working and running well, but refuse to release it until official shuts down (which I fully respect, and expect, even if I hate how badly SEGA butchered PSO2)
I'm by no means a PSO expert, but I have been around the scene since, minimum PSOBB official servers were still online (so minimum 20 years), and have observed the private server scene since schthack first popped up. I've put in a good 1200+h into things (which is baby time, but more than enough to form a solid, accurate opinion).
Only get into PSO if you
LOVE THE GRIND. Getting to lvl200 is only the beginning of your journey (unless you get suuuuuuuuuuuper lucky). You have to remember the SEGA drop rates were in the 1/20000+ territory, with some of the rarest, most sought after items having drop rates that were statistically impossible to obtain, depending on the Section ID. Expect to grind for hundreds to over a thousand hours for a single item if you are playing unmodified PSO version (official SEGA DC and GC version). This is Monster Hunter grind on steroids.
PSO is all about playing on Ultimate difficulty and grinding for the perfect gear for your character. Ephinea is the best PSOBlueBurst experience, and considering the player base is actually increasing (which shocked me, but PSO is quite addicting with friends), there's no better reason than now to get into online PSOBB.
Now, IMHO:
As for THE VERSION to play offline and single player, you should ONLY consider the GameCube
Phantasy Star Online Version I & II Return to Ragol v.1.0.3 romhack by The GMK (The Great MrKid). What this romhack does is make the grind MUCH more palatable, severely toning down the drop rates, allowing more diversity of weapon and armor usage by balancing some of the items and completely changing the way some of the items work (a saber would only hit a single enemy in the official version, but in RtR, it hits up to 3 enemies at the same time, which makes sense when watching the animation), and changing many things about the game that just makes sense, adding a QoL PSO so desperately needed.
Even better, RoR can actually go online using ragol.org's PSOGC server. (As a side note, I am not getting into the drama with ragol.org. I am just stating facts here about the options available. The player can determine if they want to use the server or not). Of course, you can also host your own server if you want to cut your teeth getting into server hosting with newserv, but that is beyond the scope of this topic.
Either way, you have options to play online with RtR if you want, but being able to fire up Dolphin, boot up RtR with 3 other friends on a huge monitor/TV, and actually enjoy the gameplay loop with great QoL features and feeling like you're actually making progress (instead of spending literal hundreds of hours for just basic things like stat maxing and Add Slots for armors...) is just incredibly satisfying.
Seriously, if you love the feel of the PSO universe, you need to give Return to Ragol a try! It's seriously everything I ever would've wanted in a romhack of PSOvI&IIPlus.
As an aside:
Many of the PSOv1&IIPlus Dolphin AR codes that Aleron Ives and Ron have created work with RtR, so if you want to tweak something more about the game, you can do that as well! There's many of them, and a bit of search engine wizardry will easily find them.
So, even if you don't want to play a romhack, you can always try and tweak the base game with AR Codes.
I understand the PSO/PSU/Phantasy Star Portable/Zero series isn't for everyone, but if you love grinding and a really cool sci-fi setting, they are definitely worth investing time into.