in .ddev folder add a file .ddev/php/xdebug.ini
with this:
xdebug.remote_host=10.254.254.254
in PHPStorm in the preferences \ PHP \ Debug \ DBGp Proxy
Host: 10.254.254.254
Port: 9000
in terminal run
sudo ifconfig en0 alias 10.254.254.254 255.255.255.0