I have created 2 differents worlds, on both of them I searched for 3 basic caves, and I found axolotls in every single one of these caves, not being Lush Caves. They spawned in water sources like this one showed below
Linked issues
duplicates 1
Attachments
Comments 2
Since 21w13a Axolotls spawn naturally in caves below Y-level 63.
Duplicate of MC-222302, which was later resolved as "Works As Intended".