I'm a little confused here,
Correct me if I am wrong, my understandings are follow;
the A321LR is just a current production high MTOW variant of A321Neo with extra ACTs that can be converted back to a regular A321Neo if needed.
The A321XLR is a permanent modification of the current A321Neo with larger (or extra) permanent centre fuel tanks + some other minor modifications which is a separate variant that cannot be converted back into a regular A321Neo.
If this is the case, I can see A321LR still has its own niche and will still be produced for those who want to have greater flexibility within their fleet.