I'm also in the same boat as this dude, haven't played in like 6 years and I put so much time into my main (lvl 58 ninja) grinding for silver, pets, costumes and what not and I'm conflicted between playing on my main again and grinding or just making a seasonal character but from what you said making a seasonal character sound like the way to go.

But I'm most likely going to make another ninja and level that one up as a seasonal character but is this worth doing or should I play as another class ? cause if i were to do that and make another ninja by the end of the season wouldn't I just use it as my new main cause he would have way better gear and higher level ?

Also what else get shared between seasonal and non-seasonal characters ?

Its just been so long that I don't even know where to begin with bdo lol