I believe LBT should be able to detect the LP64 interface and forward those symbols.
julia> using LinearAlgebra
julia> using Libdl; libacc = dlopen("/System/Library/Frameworks/Accelerate.framework/Accelerate")
Ptr{Nothing} @0x00000003e1f58480
julia> BLAS.lbt_forward(libacc; clear=true, suffix_hint="")
signal (11): Segmentation fault: 11
in expression starting at REPL[3]:1
_ZN5dyld39MachOFile8trieWalkER11DiagnosticsPKhS4_PKc at /usr/lib/dyld (unknown line)
Allocations: 785624 (Pool: 785337; Big: 287); GC: 1