That’s Dorico users must sacrifice at this moment.
All ASIO-dependent applications on macOS have to do audio-related matters in this way. All Steinberg applications on macOS at this moment are obliged to use and only use ASIO for direct audio processing, regardless that it is bridged to macOS native CoreAudio (which is directly used by non-Steinberg pro audio apps like Logic Pro X, Studio One, Ableton Live, etc.). // I guess this policy reduces the workload of developing cross-platform softwares, AND it can let Steinberg softwares take advantages from some ASIO-accelerated audio hardwares.
For all people who encountered audio-engine-related system-resource-busy or sleeping issues (like what addressed in posts above), please do the same test with the latest available public build of Cubase Elements (free for 30 days trial or 60 days during this stay-home period). If your issue persists, then the issue may need to be troubleshooted by audio engine team in Steinberg headquarters, not the team at Her Majesty’s doorstep. However, if your issue only happens with Dorico, then you can continue reporting your encounters here.
P.S.: Sorry for my survivorship bias, but Dorico 3.1.x sleeps well on my MacBook Pro 2017 running Catalina. I suggest turning off the Adobe Creative Cloud app.