RPi4 w/ Centos and RPI.GPIO: can't add edge detection - python-3.x

Question

I am running CentOS7 with kernel 5.4.206-v8.1.el7 on a RPi4 and I am trying to setup edge detection on GPIO with RPi.GPIO-0.7.1-py3.9 (*)
I am getting the following error whatever the pin I try to configure:
RPi.GPIO.add_event_detect(self.pin, RPi.GPIO.BOTH, self._on_event) RuntimeError: Failed to add edge detection
I also get it when I run in sudo. I previously tuned the permissions to get:
[blabla#hostname]$ ls -l /dev/gpiomem crw-rw----. 1 root gpio 246, 0 Jan 1 1970 /dev/gpiomem
so that GPIO in output mode (to blink a LED for instance) works fine.
Running my basic RPi.GPIO-based edge detection code (*) with strace I noticed a few suspicious lines:
faccessat(AT_FDCWD, "/sys/class/gpio/gpio6", F_OK) = -1 ENOENT (No such file or directory) openat(AT_FDCWD, "/sys/class/gpio/export", O_WRONLY) = -1 EACCES (Permission denied)
I thought RPi.GPIO was now based on GPIO character and not sysfs anymore? Although I am far from being an expert so I may be wrong / confused
I looked a bit into /sys/class/gpio on my RPi:
[blabla#hostname]$ ls /sys/class/gpio/ export gpiochip446 gpiochip454 unexport
It seems to me that attempting to create /sys/class/gpio/gpio6 makes no sense here, one should read the base of the controller and do base+6 ? Wouldn't that explain the Permission denied?
I tried to run the event.c example of the bcm2835 library and this works fine, ie button pressed are detected correctly. For technical reasons I would like to use RPi.GPIO.
Sorry again I am far from being an expert so maybe just confused myself, any help to unblock the situation would be great!
Thanks a lot
Best wishes
(*)
import RPi.GPIO as GPIO
X=6
# Set pin X in GPIO mode
GPIO.setmode(GPIO.BCM)
GPIO.setup(X, GPIO.IN, pull_up_down=GPIO.PUD_UP)
# Define a callback function to detect edge events
def my_callback(channel):
print(f"Edge event detected on pin {X}")
# Set the callback function
GPIO.add_event_detect(X, GPIO.RISING, callback=my_callback)
# Main loop
try:
while True:
pass
# Exit gracefully
except KeyboardInterrupt:
GPIO.cleanup()