Server Issues

I'm Very... very upset. Me and my friends were looking for some kinda of relax and boom... lag in the server. We put 30 mods, mods that can run on potato pc and the server lags. I cannot stand this, i think its for the ram. My Connection is Good, Either of my friend's connection so what's wrong? Why can't i play with 30 mods? Could it be for Decocraft? Because it's too heavy? Please help me because i cannot play in that way

1.12.2 Version

Well, my cpu sucks but even my friends that have a better cpu than me experience this lag so...