Maybe it should be an EffectLib issue.

I have spells with large particle effects, however if there are more than 8 players nearby, severe network lag will occur, I guess it was caused by sending too many particle packets to every clients.

So I wonder if this can help address it: Limit max particle amount to 5 players(can be configured), and if nearby players are less than 5, everyone will see all particles normally, otherwise, for example, when there're 8 players nearby, only 500%(100% for 1 player limit) particles will be sent to all players in total, which means each player can only see 62.5% particles, and the other 37.5% are just canceled.

I think this solution can lower the network pressure and deal less impact on visual effect.