If you use RSA keys in repositories, add at the end of the script as described above^
CALL "C:\Program Files\Git\cmd\start-ssh-agent.cmd"
...
"C:\Program Files\Git\usr\bin\ssh-add" ~/.ssh/myid.rsa
Works with Git 2.24.0, TortoiseGit 2.9.0, Windows 10 and no any Putty using.