I can confirm that the Cisco-internal tool SoX is still in-use and Cisco support can translate XE configs into XR configs. There is some level of sanity-checking involved and it may not match your intent, but it saves a LOT of time to get the base XR template from XE, which can be modified.
We had a Cisco XE specialist and an XR specialist on a phone call during a regular sync meeting with Cisco at our company, and they collaborated and provided an output XR file using SoX based on an XE config that I gave them. They provided this file same-day, so it appears to be a quick process.
Output at the top of the converted file:
!
! Configuration file converted by:
!
! SoX Tool (v50.00) [http://xrgeeks.cisco.com/sox/Sox_Tool.html]
! for IOS-XR Release (R5.3) at 21:10:41 12/03/24 UTC
!
!
! Caveat Emptor: This file has been generated by an automated tool.
! No guarantee is offered with respect to accuracy
! and/or suitability of the results.
!
! The consumer of this file is responsible to:
!
! o apply appropriate sanity-checking
! o detect omissions
! o correct errors
!
!
!
!
