I would not call it a common problem, rather the opposite considering how popular the Ender models are and given the fact that there are a mere handful of such problem reports among 41,000 posts here.
That having said:
- Make sure to carefully follow each instruction item on top of klipper/config/printer-creality-ender3-v2-2020.cfg at master · Klipper3d/klipper · GitHub
- Make sure that your board really has the mentioned STM MCU. Creality has a bad habit of silently changing their boards around
- Make sure you use SD cards below 8GB and experiment with different SD cards when not working. Some boards are very picky
- Make sure to use good quality USB cables
- Make sure your Linux OS is not suffering from any bugs, e.g. BRLtty / ModemManager - Services Interfering with Klipper and Debian 11 (Bullseye) udev bug - No board or serial found
- Use the dmesg procedure and the
lsusbcommand to verify if the board is even registered in the Linux OS.