Add a password hash provider to handle BCrypt passwords inside Keycloak.
./gradlew jarcp build/libs/keycloak-bcrypt-1.6.0.jar docker/
docker-compose up -dcurl -L https://github.com/ommsolutions/keycloak-bcrypt/releases/download/1.6.0/keycloak-bcrypt-1.6.0.jar > KEYCLOAK_HOME/standalone/deployments/keycloak-bcrypt-1.6.0.jar
You need to restart Keycloak.
Go to Authentication / Password policy and add hashing algorithm policy with value bcrypt.
To test if installation works, create new user and set its credentials.