Harmonizing with your equipment is the best way to increase your keeper rate.
Absolutely true, but to fully harmonise with your equipment you need to find a system you can connect with
A skilled photographer should be able to make any platform work but when there's an emotional connection with the used gear creativity can flow freely unhindered from any frustrations, big or small.
Whatever capabilities and features add up to connect is mostly subjective, besides the common things like built, button layout, size, ISO, IQ, sensor size, lens character, etc I like features like a metal camera body, metal lenses, aperture rings, etc to complete the picture, pun untended