This game trash like Sword/Shield and Arceus or should I pick it up pre-owned when it's "fixed"?
Theres not knowing if this big patch will really works all the bugs or not. Unfortunatelly you have to wait until it launches.
But if you wanna try to compare well...the game is really not good. Like, it gives you a sense of freedom but it sacrifices everything in the process. You don't need to fight trainers(90% of trainers have either 1 or 2 mons, so fighting them is pointless besides getting TM rewards), you can just skip ahead and train with high level mons and farm xp and beat leaders with ease. Theres no sense of objective, because those look more like "side-quests" than objectives. Gym leaders are more akin to scavenger hunt rather than something actually serious and the open-world is terrible, mostly consisting in cliffs and mountains. Might be the worst open world ever made. And like I said, raids are broken mostly with confusing AI, sometimes the text doesn't even properly appear, enemies bugging their turns which also results in glitch where either you can't do nothing(they say they will fix this in this patch) or your mon keep frozen like a statue, enemies don't take damage, etc. I think the only good thing I could say in this game is that the mechanic of your first mon following you is cool. I don't like the auto-battle, but it's cool seeing it following you.
If anything this game happens to be worse than Sword/Shield and those 2 are really terrible games.
If you're really don't care and just want to play pokemon then go for it. But be prepared by a very shallow experience.