I understand that CLKUSR has to be available at power-up. However after configuration and calibration are complete, can CLKUSR be turned off? There's a concern about noise on the board and if it's no longer being used, might want to turn off CLKUSR.
Based on my knowledge, I don't think you can turn off CLKUSR after configuration.
You can enable CLKUSR as the initialization clock source (Device and Pin Options ➤ General➤ Device initialization clock source ➤ CLKUSR pin). However, to turn it off after configuration, I think you cannot do that.