Hello.
Our servers require a jump, Putty works ok using the format:
user1@user2@server1@server2
And the path to the key file.
If I import it into RDM it works but converting it to native RDM SSH (v2021.2.22) creates a no-valid entry.
Converted RDM entry keeps asking for an user name and if typed connection ends with error (attached pic)

MobaXterm also works, could you please help?
After playing a bit I have found the trick, WinSCP gave me a clue
in host add:
server2
In user
user1@user@host1
Tricky solution.
Hello,
Thank you for contacting us on that matter!
Also, thank you for your feedback! I am glad to see that you have found a solution.
Best regards,
James Lafleur