I wouldn't. We have been trying[1]; humans are genuinely shocking in this way. Mechanical systems should have so many advantages over humans; springs are 10x better than tendons, motors are 3x better than muscles. It's possible humans evolved walking as a predatory tactic. Even if we develop a super-efficient walking robot, humans are efficient at several speeds, and keep that efficiency while varying their stride and foot placement, and with one of the largest most complex brains of any animal. And the ratio of leg/torso length is pretty variable among humans! Not to mention the flexible spine and swinging hips should be a huge energy sap, but they just kind of... aren't.

Beating human locomotion in the general case is pretty far off. It's a combination of body plan, extreme optimization of joints and energy storage, and really good algorithms.

One killer feature of the human body is synovial fluid. It's very thin, non-newtonian, self-replenishing and contained in particularly low-friction bearing surfaces. It's certainly better than 99.9% of mechanical joints, because these surfaces filter, heal and re-lubricate themselves. Mechanical joints have sticky grease so they stay lubricated without maintenance, and work in the presence of water and grit. It's doubtful that any joint that doesn't heal itself can compete, long-term.

[1]: https://spectrum.ieee.org/durus-sri-ultra-efficient-humanoid...