My understanding, from watching streams by (mostly) german speaking real life A320 pilots, is that AT on/off during approach and landing is an airline SOP question.
Apparently the SOP for most german operators (eg. Lufthansa group airlines) is that manual landing should be done with AT off, aka manual flight and manual thrust for proficiency reasons.
I hope someone can confirm.
For me personally I used to always have AT on during landing, but recently I’m trying to get better handling of manual thrust, so I land with manual thrust. Usually hand fly once established.