For legged, you want high torque and backdriveability (for shock absorption).
Agricultural drone motors like the eaglepower 8308 are ideal.
They’re cost effective, (~$80 from aliexpress) & you can pair them with a 3d printed cycloidal drive to fulfill both requirements.
Industry actuators are an order of magnitude more expensive than this.
Extra: If you go down this path, you’ll need a driver. The Xdrive is frequently recommended, but there’s a clone that’s significantly cheaper: https://makerbase3d.com/product/makerbase-xdrive-mini-high-p...