Line in or XLR in?

this is my configuration. i have a behringer xair 16 mixer with several instruments connected.

from two aux channels XLR I go out and enter in the line inputs of the UR 44. do you think it is better to use the line inputs or the Front XLR inputs?

Thank you foto your help!

It’s imho best to use line inputs 3&4 as they are fixed volume.