Thanks s2sailor, I did an uninstall, appclear, reinstall from the website and unfortunately it's still happening. I just haven't had time to gather information for support yet. What I don't get is why I'm seeing this but not many other people seem to be hitting it. I see it across two different Macs, both on Sonoma, an M1 with 16gb, and an M2 with 32gb. I see it both in the desktop client and in the web client. I don't have any special virus scanners or special utilities running, just fairly clean Macs. It takes about 10 seconds for a sentence to show up after I've typed it.
Through looking in the profiler in the Chrome dev tools, I'm pretty convinced that something changed with respect to key press event handlers and how / when things are rendered in either Evernote or Chromium. I thought it might be Chromium / Electron but I see the same lag, actually worse, in Safari, so I'm leaning toward Evernote at this point.
I need to gather information and get it off to support. Thanks.