Crummy mutli-core performance is totally expected. When you do something super-stupid, like no hyperthreading, it's going to perform like a CPU with fewer cores. The CPU isn't playing with a full deck, just like the idiots that decided hyperthreading needed to go. That level of stupid can't be tolerated. They need to be fired, beaten and thrown in a dumpster.
Intel's upcoming 'Arrow Lake-S' Core Ultra 9 285K desktop CPU boasts quite the punch in terms of single-threaded performance. Due to its lack of hyper-threading support, however, falls way back in the pack in multi-threaded scores, ending up losing not just to AMD's Ryzen 9 9950X, but also its own predecessor - the Core i9-14900K.