Re: If key exchange fails, move on to next one
Everything is up to date, including FileZilla, and it works on a clean install that just has the base windows (from an vm image). I install everything new to ensure it's clean. I don't know how FileZilla does key exchanges. But WinSCP fails on all machines on the default first ECDH.
Can you post a verbose FileZilla log file?
If we are passing a list either through the UI or through the rawsettings parameters, then what is the purpose of the list? It should just take one value in that case.
The purpose of the list is to set your preferences. WinSCP will automatically pick the first algorithm that the server also supports. If the server starts supporting a more preferred algorithm in the future, WinSCP can start using it. That would not be possible, if it was a single value option.