While Mac got a 64-bit engine, the of Borderlands 2 officially remains a 32-bit application.
: The 64-bit update was the gateway for the Ultra HD Texture Pack on Steam. It allowed the game to load higher-resolution textures for characters, vehicles, and environments without choking on the data. borderlands 2 64 bit
There is a rumor (unconfirmed as of late 2024) that Gearbox is testing an internal 64-bit build for the rumored definitive edition. Until then, the community relies on LAA. Quick guide — Borderlands 2 64-bit Windows version