CR6-SE fails to heat hotend to set point
Perform PID calibration procedure for hotend using G-code 'M303' with nozzle fans turned off completely.
You may use detailed guidelines from AK Eric's blog, RepRap wiki or 3DMaker Engineering.
If this will improve or clearly change the situation, but you still observe some issues during or after tuning, review other posts for troubleshooting. For example: large initial overshoot, no oscillations, struggle to fit into functional range or narrowed down hardware issues of incorrect heating cartridges.
When succeeded, you should repeat the procedure with fans enabled at the regular speed you use during printing.
PID calibration can be performed from Marlin's LCD menu (Configuration &gt; Advanced Settings &gt; Temperature &gt; PID Autotune E1). It will allow to select target temperature, but not number of tuning cycles. It is only accessible when PID_AUTOTUNE_MENU is enabled in firmware settings (Configuration.h):
//#define PID_EDIT_MENU         // Add PID editing to the &quot;Advanced Settings&quot; menu. (~700 bytes of PROGMEM)
#define PID_AUTOTUNE_MENU     // Add PID auto-tuning to the &quot;Advanced Settings&quot; menu. (~250 bytes of PROGMEM)