I’ve also had the same problem with the mDNSResponder since upgrading to Ventura (and yes, I’ve the current version of Ventura, and have even tried reinstalling)–it kicks in and takes over 97%+ of the CPU processes, causing excessive heat and then excessive fan usage. Killing the process is only temporary. Even the above ps and sudo kill -9 suggestion doesn’t stop it from coming back on again and again. I have to kill it every few minutes just to keep the fans from over-running. I thought of downgrading back to Monterey but that’s not an easy process. I’d even try an automator script if I could come up with one that would kill just this process when it shows up in activity monitor, but my scripting skills don’t seem up to the…task. BTW, this is a Intel i9 2019 16" MBP.
mDNSResponder definitely is killing the pleasure of using a Mac