is it possible to edit the SSH Gateway (jump host) hostname for multiple entries as a batch edit? If so, how could this be done?
this can be accomplished with the Custom Powershell Command feature
Select all your entries => navigate to Custom Powershell Command => enter this command and click OK:
$connection.Terminal.UseSSHGateway = "True"
$connection.Terminal.SSHGatewayHost = "188.8.131.52"
I recommend to do a backup before you execute the command against your sessions!