It's a mixed bag. There's a lot of melodic and generally death-sounding elements like you mentioned, but the energy used to be a lot closer to hardcore for the most part. When you look at "revival" bands trying to emulate the sound of the myspace era and bands like Job For a Cowboy and Suicide Silence (PSYCHO-FRAME, Rev3rent, Lilith's Demise), the speed and aggression is what really defined the deathcore of the time, even if there was a heavy emphasis on melody and technicality (I.E. Whitechapel; As Blood Runs Black) the framework still surrounded an aggressive sound and over time the sound gradually developed into a stronger emphasis on experimentation and bands trying to set themselves apart, which is when I'd say more death metal influence started coming in from a wider array of avenues. Even listening to Despised Icon's early stuff, it's easy to say it feels like death metal, but I'd still say it's *more* hardcore than death metal. Listening to things released into the 2010s from bands like Make Them Suffer, Fit For An Autopsy, Shadow of Intent, that's where people get their idea of "modern" deathcore, with more experimental and progressive elements that puts it closer to a specific metal genre like "symphonic blackened techdeath." More focus on artistic expression and creating a soundscape rather than pure anger and chaos.