SMT or multi-threading was a workaround for vendors to pump up their thread count without adding on-die memory for each thread.
There are applications where it is beneficial, but for over a decade best practice in the enterprise space was to disable hyper-threading and watch the benchmarks soar.
This has to do with memory locks during actual workloads, not synthetic benchmarks as servers see erratic data loads.
Not out of the blue, we’ve been instructed to disable it as above for performance and security in the enterprise space since day 0.
There was a white paper in the early 2010’s regarding speculative execution attacks. It has not gotten better and hyper-threading is the same.