Hi,
I have more or less the same issue: everything’s connected (GPIO4, 3.3V, GND, 4,6kOhm resistor), “dtoverlay = w1-gpio” added in /boot/config.txt but got the error: “ERROR (SyncWorker_4) [homeassistant.components.sensor.onewire] No onewire sensor found. Check if dtoverlay=w1-gpio is in your /boot/config.txt. Check the mount_dir parameter if it’s defined”.
If I type via SSH: “ls -l /sys/bus/w1/devices/”, I get the following message: “ls: /sys/bus/w1/devices/: No such file or directory”, and actuall “w1” folder is missing. So I cannot get the Id of the DS 18B20 that is connected.
2 things I can think right now: One is that you have left a space between the words. I dont know if it matters, but in the guide there are no spaces. I also checked my config and there are no spaces too. Try it without spaces, please. Dont forget to reboot.
dtoverlay=w1-gpio
If you just removed the spaces but still no luck, then the second thing I can think of is the wiring. Something must be off. Make sure you have the flat side of the sensor facing you, the left pin is the ground and the right is the power. Also the resistor has to be between data and power.