I don't think there is anything in particular. Since lineage 2 is so old, current era of computers are more then capable of running multiple instances without any hiccups. I would suggest go for 144Hz monitor and wired mouse and keyboard. Any type would do the job. The other and i would say without a doubt the most important one is your internet connection, if your ISP offers fiber internet go for it, its a game changer. That's pretty much it