# 1  Create a dedicated user
sudo adduser new_username   # choose a strong password

# 2  Let that user sudo *only* when really needed
sudo usermod -aG sudo new_username

# 3  Switch to it
su - new_username

# 4  Copy your SSH key so you can log in directly
mkdir -p ~/.ssh && chmod 700 ~/.ssh
cat /tmp/your_pubkey.pub >> ~/.ssh/authorized_keys
chmod 600 ~/.ssh/authorized_keys