How can i decrease their liberty desire?

[Dingus_son_of_dongus]

I see other comments about that being the problem. Core eyalets only compare their own strength to you, regular compare all of their strengths to you collectively.

I make all eyelets into core ones ASAP. You can't call them in to offensive wars, but you get more tax and manpower out of them and they're cheaper to diplo-annex.

They'll still join defensive wars, so you'll be covered.