This actually should work. You just need to copy the content of the pem file to the private part of the key when copying it into Termius app in the Keychain section.
We’ll double-check it.
If you have any other problems please contact us here – http://support.termius.com/
An error occurred while saving the commentjordan commented
same issue. unsupported key format. Need a way to point to a .pem file.