Which order of Catholic priests is the one true order?
idiot
Is this a serious question? You could do some research on the internet to find out information on the various orders of priesthood associated with the Catholic Church to find out.
None, as the NT church never ordained anyone as an separate class of believers distinctively titled “hiereus”="priests," but presbuteros (senior/elder) or episkopos (superintendent/overseer), that being one office. (Titus 1:5-7)
Nor did they engage in a unique sacrificial function, such as preparing and dispensing physical food as their primary ordained function, as an expiation for sins, and which is then physically consumed to gain spiritual and eternal life
Instead, prayer and preaching as shepherds was their manifest distinctive primary function, and which word is what is said to "nourish" the souls of believers, and believing it is how the lost obtain life in themselves. (1 Timothy 4:6; Psalms 19:7;Acts 15:7-9)