JJOS 2XL doesn’t use the big screen. It is the biggest standard version with most features. JJOS 3 is the follow up which is loaded with features as well but has some workflow differences. It’s a question of what works better for you, but you don’t have to decide because the license for JJOS 3 is included in JJOS 2XL and you can switch as you like.
The big screen version is the JJOS 128XL which only works if you have the extended screen from mpcstuff installed.